diff --git a/src/Controller/GroupController.php b/src/Controller/GroupController.php
index 87bf0df..be6c072 100644
--- a/src/Controller/GroupController.php
+++ b/src/Controller/GroupController.php
@@ -45,6 +45,7 @@ class GroupController extends AbstractController
         $group = new Group();
         $group->addUser($this->getUser());
         $group->setStatus(Group::ACTIVE);
+        $group->setOpen(true);
 
         $this->denyAccessUnlessGranted(GroupVoter::SUBMIT, $group);
 
@@ -130,6 +131,25 @@ class GroupController extends AbstractController
         return $this->redirectToRoute($isAdmin ? 'app_admin_group' : 'app_user_group_view', ['id' => $group->getId()]);
     }
 
+    #[Route('/admin/group/subscribe/{id}', name: 'app_admin_group_subscribe')]
+    #[Route('/user/group/subscribe/{id}', name: 'app_user_group_subscribe')]
+    public function subscribe(int $id, Request $request, GroupRepository $groupRepository, EntityManagerInterface $em): Response
+    {
+        $group = $groupRepository->find($id);
+        if (!$group) {
+            throw new NotFoundHttpException('La ressource demandée est introuvable.');
+        }
+
+        $this->denyAccessUnlessGranted(GroupVoter::CANSUBSCRIBE, $group);
+
+        $group->addUser($this->getUser());
+        $em->flush();
+
+        $isAdmin = str_starts_with($request->attributes->get('_route'), 'app_admin');
+
+        return $this->redirectToRoute($isAdmin ? 'app_admin_group' : 'app_user_group_view', ['id' => $group->getId()]);
+    }
+
     #[Route('/admin/group/delete/{id}', name: 'app_admin_group_delete')]
     #[Route('/user/group/delete/{id}', name: 'app_user_group_delete')]
     public function delete(int $id, Request $request, GroupRepository $groupRepository, EntityManagerInterface $em): Response
@@ -174,6 +194,7 @@ class GroupController extends AbstractController
             'routecancel' => $isAdmin ? 'app_admin_group' : 'app_home',
             'routedelete' => $isAdmin ? 'app_admin_group_delete' : 'app_user_group_delete',
             'routemove' => $isAdmin ? 'app_admin_group_move' : 'app_user_group_move',
+            'routesubscribe' => $isAdmin ? 'app_admin_group_subscribe' : 'app_user_group_subscribe',
             'group' => $group,
         ]);
     }
diff --git a/src/Controller/ProjectController.php b/src/Controller/ProjectController.php
index 95a255f..8514656 100644
--- a/src/Controller/ProjectController.php
+++ b/src/Controller/ProjectController.php
@@ -47,6 +47,7 @@ class ProjectController extends AbstractController
         $project = new Project();
         $project->addUser($this->getUser());
         $project->setStatus(Project::DRAFT);
+        $project->setOpen(true);
 
         $this->denyAccessUnlessGranted(ProjectVoter::SUBMIT, $project);
 
@@ -161,6 +162,25 @@ class ProjectController extends AbstractController
         return $this->redirectToRoute($isAdmin ? 'app_admin_project' : 'app_user_project_view', ['id' => $project->getId()]);
     }
 
+    #[Route('/admin/project/subscribe/{id}', name: 'app_admin_project_subscribe')]
+    #[Route('/user/project/subscribe/{id}', name: 'app_user_project_subscribe')]
+    public function subscribe(int $id, Request $request, ProjectRepository $projectRepository, EntityManagerInterface $em): Response
+    {
+        $project = $projectRepository->find($id);
+        if (!$project) {
+            throw new NotFoundHttpException('La ressource demandée est introuvable.');
+        }
+
+        $this->denyAccessUnlessGranted(ProjectVoter::CANSUBSCRIBE, $project);
+
+        $project->addUser($this->getUser());
+        $em->flush();
+
+        $isAdmin = str_starts_with($request->attributes->get('_route'), 'app_admin');
+
+        return $this->redirectToRoute($isAdmin ? 'app_admin_project' : 'app_user_project_view', ['id' => $project->getId()]);
+    }
+
     #[Route('/admin/project/delete/{id}', name: 'app_admin_project_delete')]
     #[Route('/user/project/delete/{id}', name: 'app_user_project_delete')]
     public function delete(int $id, Request $request, ProjectRepository $projectRepository, EntityManagerInterface $em): Response
@@ -205,6 +225,7 @@ class ProjectController extends AbstractController
             'routecancel' => $isAdmin ? 'app_admin_project' : 'app_home',
             'routedelete' => $isAdmin ? 'app_admin_project_delete' : 'app_user_project_delete',
             'routemove' => $isAdmin ? 'app_admin_project_move' : 'app_user_project_move',
+            'routesubscribe' => $isAdmin ? 'app_admin_project_subscribe' : 'app_user_project_subscribe',
             'project' => $project,
         ]);
     }
diff --git a/src/Entity/Group.php b/src/Entity/Group.php
index 41d5e2b..aca2902 100644
--- a/src/Entity/Group.php
+++ b/src/Entity/Group.php
@@ -29,6 +29,9 @@ class Group
     #[ORM\Column(type: 'text', nullable: true)]
     private ?string $description = null;
 
+    #[ORM\Column(type: 'boolean', nullable: false)]
+    private bool $open;
+
     #[ORM\Column]
     private string $status;
 
@@ -95,6 +98,18 @@ class Group
         return $this;
     }
 
+    public function isOpen(): bool
+    {
+        return $this->open;
+    }
+
+    public function setOpen(bool $open): static
+    {
+        $this->open = $open;
+
+        return $this;
+    }
+
     public function getStatus(): string
     {
         return $this->status;
diff --git a/src/Entity/Project.php b/src/Entity/Project.php
index c18e43e..1280c27 100644
--- a/src/Entity/Project.php
+++ b/src/Entity/Project.php
@@ -36,6 +36,9 @@ class Project
     #[ORM\Column(type: 'string', length: 20)]
     private string $nature;
 
+    #[ORM\Column(type: 'boolean', nullable: false)]
+    private bool $open;
+
     #[ORM\Column]
     private string $status;
 
@@ -131,6 +134,18 @@ class Project
         return $this;
     }
 
+    public function isOpen(): bool
+    {
+        return $this->open;
+    }
+
+    public function setOpen(bool $open): static
+    {
+        $this->open = $open;
+
+        return $this;
+    }
+
     public function getStatus(): string
     {
         return $this->status;
diff --git a/src/Form/GroupType.php b/src/Form/GroupType.php
index b8e7518..73fc3f4 100644
--- a/src/Form/GroupType.php
+++ b/src/Form/GroupType.php
@@ -7,6 +7,7 @@ use App\Entity\User;
 use Bnine\MdEditorBundle\Form\Type\MarkdownType;
 use Symfony\Bridge\Doctrine\Form\Type\EntityType;
 use Symfony\Component\Form\AbstractType;
+use Symfony\Component\Form\Extension\Core\Type\CheckboxType;
 use Symfony\Component\Form\Extension\Core\Type\DateType;
 use Symfony\Component\Form\Extension\Core\Type\SubmitType;
 use Symfony\Component\Form\Extension\Core\Type\TextareaType;
@@ -38,8 +39,13 @@ class GroupType extends AbstractType
             'label' => 'Résumé',
         ])
 
+        ->add('open', CheckboxType::class, [
+            'label' => 'Groupe Ouvert',
+            'required' => false,
+        ])
+
         ->add('users', EntityType::class, [
-            'label' => 'Propriétaires',
+            'label' => 'Paticipants',
             'class' => User::class,
             'choice_label' => 'username',
             'multiple' => true,
diff --git a/src/Form/ProjectType.php b/src/Form/ProjectType.php
index 95cb679..681dc88 100644
--- a/src/Form/ProjectType.php
+++ b/src/Form/ProjectType.php
@@ -7,6 +7,7 @@ use App\Entity\User;
 use Bnine\MdEditorBundle\Form\Type\MarkdownType;
 use Symfony\Bridge\Doctrine\Form\Type\EntityType;
 use Symfony\Component\Form\AbstractType;
+use Symfony\Component\Form\Extension\Core\Type\CheckboxType;
 use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
 use Symfony\Component\Form\Extension\Core\Type\DateType;
 use Symfony\Component\Form\Extension\Core\Type\SubmitType;
@@ -39,6 +40,11 @@ class ProjectType extends AbstractType
             'label' => 'Résumé',
         ])
 
+        ->add('open', CheckboxType::class, [
+            'label' => 'Projet Ouvert',
+            'required' => false,
+        ])
+
         ->add('nature', ChoiceType::class, [
             'label' => 'Nature',
             'choices' => [
@@ -49,7 +55,7 @@ class ProjectType extends AbstractType
         ])
 
         ->add('users', EntityType::class, [
-            'label' => 'Propriétaires',
+            'label' => 'Paticipants',
             'class' => User::class,
             'choice_label' => 'username',
             'multiple' => true,
diff --git a/src/Security/GroupVoter.php b/src/Security/GroupVoter.php
index ebf190a..79a8427 100644
--- a/src/Security/GroupVoter.php
+++ b/src/Security/GroupVoter.php
@@ -17,10 +17,11 @@ class GroupVoter extends Voter
     public const MOVETOACTIVE = 'MOVETOACTIVE';
     public const MOVETOINACTIVE = 'MOVETOINACTIVE';
     public const TOME = 'TOME';
+    public const CANSUBSCRIBE = 'CANSUBSCRIBE';
 
     protected function supports(string $attribute, $subject): bool
     {
-        $attributes = [self::VIEW, self::SUBMIT, self::UPDATE, self::DELETE, self::MOVETOACTIVE, self::MOVETOINACTIVE, self::TOME];
+        $attributes = [self::VIEW, self::SUBMIT, self::UPDATE, self::DELETE, self::MOVETOACTIVE, self::MOVETOINACTIVE, self::TOME, self::CANSUBSCRIBE];
 
         return in_array($attribute, $attributes) && $subject instanceof Group;
     }
@@ -76,6 +77,11 @@ class GroupVoter extends Voter
         return $group->getUsers()->contains($user);
     }
 
+    private function canSubscribe(Group $group, User $user): bool
+    {
+        return $group->isOpen() && !$group->getUsers()->contains($user);
+    }
+
     protected function voteOnAttribute(string $attribute, $group, TokenInterface $token): bool
     {
         $user = $token->getUser();
@@ -91,6 +97,8 @@ class GroupVoter extends Voter
             self::MOVETOACTIVE => $this->canMoveToActive($group, $user),
             self::MOVETOINACTIVE => $this->canMoveToInactive($group, $user),
             self::TOME => $this->toMe($group, $user),
+            self::CANSUBSCRIBE => $this->canSubscribe($group, $user),
+
             default => false,
         };
     }
diff --git a/src/Security/ProjectVoter.php b/src/Security/ProjectVoter.php
index cc6e6c2..03b0d50 100644
--- a/src/Security/ProjectVoter.php
+++ b/src/Security/ProjectVoter.php
@@ -19,10 +19,11 @@ class ProjectVoter extends Voter
     public const MOVEVOTED = 'MOVEVOTED';
     public const MOVEARCHIVED = 'MOVEARCHIVED';
     public const TOME = 'TOME';
+    public const CANSUBSCRIBE = 'CANSUBSCRIBE';
 
     protected function supports(string $attribute, $subject): bool
     {
-        $attributes = [self::VIEW, self::SUBMIT, self::UPDATE, self::DELETE, self::MOVEDRAFT, self::MOVETOVOTE, self::MOVEVOTED, self::MOVEARCHIVED, self::TOME];
+        $attributes = [self::VIEW, self::SUBMIT, self::UPDATE, self::DELETE, self::MOVEDRAFT, self::MOVETOVOTE, self::MOVEVOTED, self::MOVEARCHIVED, self::TOME, self::CANSUBSCRIBE];
 
         return in_array($attribute, $attributes) && $subject instanceof Project;
     }
@@ -97,6 +98,11 @@ class ProjectVoter extends Voter
         return $project->getUsers()->contains($user);
     }
 
+    private function canSubscribe(Project $project, User $user): bool
+    {
+        return $project->isOpen() && !$project->getUsers()->contains($user);
+    }
+
     protected function voteOnAttribute(string $attribute, $project, TokenInterface $token): bool
     {
         $user = $token->getUser();
@@ -114,6 +120,7 @@ class ProjectVoter extends Voter
             self::MOVEVOTED => $this->canMoveVoted($project, $user),
             self::MOVEARCHIVED => $this->canMoveArchived($project, $user),
             self::TOME => $this->toMe($project, $user),
+            self::CANSUBSCRIBE => $this->canSubscribe($project, $user),
             default => false,
         };
     }
diff --git a/templates/group/edit.html.twig b/templates/group/edit.html.twig
index 99aa6d5..e024a0b 100644
--- a/templates/group/edit.html.twig
+++ b/templates/group/edit.html.twig
@@ -20,6 +20,7 @@
                     <div class="card-header">Information</div>
                     <div class="card-body">
                         {{ form_row(form.title) }}
+                        {{ form_row(form.open) }}
                         {{ form_row(form.dueDate) }}
                         {{ form_row(form.users) }}
                         {{ form_row(form.summary) }}
diff --git a/templates/group/view.html.twig b/templates/group/view.html.twig
index 2911e25..b51452d 100644
--- a/templates/group/view.html.twig
+++ b/templates/group/view.html.twig
@@ -15,6 +15,12 @@
 
         <a href="{{ path(routecancel) }}" class="btn btn-secondary me-5">Retour</a>
 
+        {% if is_granted('CANSUBSCRIBE', group) %}
+            <a href="{{ path(routesubscribe,{id:group.id}) }}" class="btn btn-secondary me-1" onclick="return confirm('Participer à ce groupe ?')">
+                <i class="fas fa-users"></i> Participer à ce groupe
+            </a>
+        {% endif %}
+
         {% if is_granted('MOVETOINACTIVE', group) and group.status=="Actif"%}
             <a href="{{ path(routemove,{id:group.id, status:"INACTIVE"}) }}" class="btn btn-primary me-1" onclick="return confirm('Statut = Inactif ?')">
                 <i class="fas fa-angle-double-right"></i> Statut = Inactif
@@ -39,6 +45,7 @@
                 <div class="card-header">Information</div>
                 <div class="card-body">
                     <b>Titre</b> = {{ group.title }}<br>
+                    <b>Groupe Ouvert</b> = {{ group.open ? "Oui" : "Non" }}<br>
                     <b>A Voter pour le</b> = {{ group.dueDate ? group.dueDate|date("d/m/Y"):"" }}
                 </div>
             </div>
@@ -50,6 +57,15 @@
                 </div>
             </div>
 
+            <div class="card mt-3">
+                <div class="card-header">Participants</div>
+                <div class="card-body">
+                    {%for user in group.users%}
+                        {{loop.first ? user.username : ' - '~user.username}}
+                    {%endfor%}
+                </div>
+            </div>
+
             {{ render(path("bninefiles_files",{domain:'group',id:group.id, editable:0})) }}                
 
             <div class="card mt-3">
diff --git a/templates/home/home.html.twig b/templates/home/home.html.twig
index 68ce1ba..5d5e34f 100644
--- a/templates/home/home.html.twig
+++ b/templates/home/home.html.twig
@@ -84,7 +84,7 @@
                                     <b>A Voter pour le</b> = {{ project.dueDate|date("d/m/Y") }}<br>
                                 {% endif %}
                                 <b>Nature</b> = {{ project.nature }}<br>
-                                <b>Propriétaires</b> = 
+                                <b>Participants</b> = 
                                 {%for user in project.users%}
                                     {{loop.first ? user.username : ' - '~user.username}}
                                 {%endfor%}
diff --git a/templates/project/edit.html.twig b/templates/project/edit.html.twig
index 60953df..3a132ae 100644
--- a/templates/project/edit.html.twig
+++ b/templates/project/edit.html.twig
@@ -21,6 +21,8 @@
                     <div class="card-header">Information</div>
                     <div class="card-body">
                         {{ form_row(form.title) }}
+                        {{ form_row(form.open) }}
+                        
                         {{ form_row(form.nature) }}
                         {{ form_row(form.dueDate) }}
                         {{ form_row(form.users) }}
diff --git a/templates/project/view.html.twig b/templates/project/view.html.twig
index 00bc9c4..8e9ac31 100644
--- a/templates/project/view.html.twig
+++ b/templates/project/view.html.twig
@@ -15,6 +15,12 @@
 
         <a href="{{ path(routecancel) }}" class="btn btn-secondary me-5">Retour</a>
 
+        {% if is_granted('CANSUBSCRIBE', project) %}
+            <a href="{{ path(routesubscribe,{id:project.id}) }}" class="btn btn-secondary me-1" onclick="return confirm('Participer à ce projet ?')">
+                <i class="fas fa-users"></i> Participer à ce projet
+            </a>
+        {% endif %}
+
         {% if is_granted('MOVETOVOTE', project) and project.status=="Brouillon"%}
             <a href="{{ path(routemove,{id:project.id, status:"TOVOTE"}) }}" class="btn btn-primary me-1" onclick="return confirm('Statut = à Voter ?')">
                 <i class="fas fa-angle-double-right"></i> Statut = à Voter
@@ -59,6 +65,7 @@
                 <div class="card-header">Information</div>
                 <div class="card-body">
                     <b>Titre</b> = {{ project.title }}<br>
+                    <b>Projet Ouvert</b> = {{ project.open ? "Oui" : "Non" }}<br>
                     <b>Nature</b> = {{ project.nature }}<br>
                     <b>A Voter pour le</b> = {{ project.dueDate ? project.dueDate|date("d/m/Y"):"" }}
                 </div>
@@ -71,6 +78,15 @@
                 </div>
             </div>
 
+            <div class="card mt-3">
+                <div class="card-header">Participants</div>
+                <div class="card-body">
+                    {%for user in project.users%}
+                        {{loop.first ? user.username : ' - '~user.username}}
+                    {%endfor%}
+                </div>
+            </div>
+
             {{ render(path("bninefiles_files",{domain:'project',id:project.id, editable:0})) }}                
 
             <div class="card mt-3">