diff --git a/src/PostIt/PostIt/Models/ChatMessage.cs b/src/PostIt/PostIt/Models/ChatMessage.cs
new file mode 100644
index 000000000..52733311a
--- /dev/null
+++ b/src/PostIt/PostIt/Models/ChatMessage.cs
@@ -0,0 +1,15 @@
+namespace PostIt.ViewModels.Chat
+{
+    /// <summary>
+    /// DTO de message de salon, calqué sur la charge envoyée par
+    /// <c>ChatHub.Send</c> côté serveur ({ Name, Room, Message }).
+    /// Le protocole JSON de SignalR sérialise en camelCase ; la
+    /// désérialisation est insensible à la casse par défaut.
+    /// </summary>
+    public class ChatMessage
+    {
+        public string? Name { get; set; }
+        public string? Room { get; set; }
+        public string? Message { get; set; }
+    }
+}
diff --git a/src/PostIt/PostIt/ViewModels/Chat/ChatViewModel.cs b/src/PostIt/PostIt/ViewModels/Chat/ChatViewModel.cs
index 54872991e..7cbdfe62f 100644
--- a/src/PostIt/PostIt/ViewModels/Chat/ChatViewModel.cs
+++ b/src/PostIt/PostIt/ViewModels/Chat/ChatViewModel.cs
@@ -45,8 +45,17 @@ namespace PostIt.ViewModels.Chat
         public partial StatusNotice Status { get; set; }
 
         [ObservableProperty]
+        [NotifyCanExecuteChangedFor(nameof(SendMessageCommand))]
         public partial bool IsConnected { get; set; } = false;
 
+        [ObservableProperty]
+        [NotifyCanExecuteChangedFor(nameof(SendMessageCommand))]
+        public partial bool HasJoinedRoom { get; set; } = false;
+
+        [ObservableProperty]
+        [NotifyCanExecuteChangedFor(nameof(SendMessageCommand))]
+        public partial string MessageToSend { get; set; } = "";
+
         // Listes dynamiques pour l'UI
         public ObservableCollection<string> Messages { get; } = new();
         public ObservableCollection<string> ConnectedUsers { get; } = new();
@@ -58,6 +67,28 @@ namespace PostIt.ViewModels.Chat
         [RelayCommand]
         public async Task JoinRoomCommand() => await JoinRoomAsync();
 
+        // Le serveur (ChatHub.Send) refuse tout message d'un utilisateur
+        // qui n'a pas joint le salon ("NoJoinNoSend") : on garde la
+        // commande inactive tant que le Join n'a pas abouti.
+        private bool CanSendMessage() =>
+            IsConnected && HasJoinedRoom && !string.IsNullOrWhiteSpace(MessageToSend);
+
+        [RelayCommand(CanExecute = nameof(CanSendMessage))]
+        private async Task SendMessageAsync()
+        {
+            if (_connection == null) return;
+            var text = MessageToSend.Trim();
+            try
+            {
+                await _connection.InvokeAsync("Send", CurrentRoom, text);
+                MessageToSend = string.Empty;
+            }
+            catch (Exception ex)
+            {
+                Messages.Add($"Erreur d'envoi : {ex.Message}");
+            }
+        }
+
         public override bool CanNavigateNext { get; protected set; } = false;
         public override bool CanNavigatePrevious { get; protected set; } = true;
 
@@ -70,6 +101,7 @@ namespace PostIt.ViewModels.Chat
                 _connection = null;
             }
             IsConnected = false;
+            HasJoinedRoom = false;
             Status = new StatusNotice("Déconnecté", StatusSeverity.Info,
              new RelayCheckCommand("Connecter", async () => await ConnectAsync()));
         }
@@ -140,11 +172,19 @@ namespace PostIt.ViewModels.Chat
                     Avalonia.Threading.Dispatcher.UIThread.Post(() =>
                     {
                         Messages.Add($"Salon rejoint avec succès : {roomInfo.Name}");
+                        HasJoinedRoom = true;
                         ConnectedUsers.Clear();
                         foreach (var u in roomInfo.Users) ConnectedUsers.Add(u);
                     });
                 });
 
+                // 4. Réception des messages du salon (diffusés par ChatHub.Send)
+                _connection.On<ChatMessage>("ReceiveMessage", (msg) =>
+                {
+                    Avalonia.Threading.Dispatcher.UIThread.Post(() =>
+                        Messages.Add($"[{msg.Room}] {msg.Name} : {msg.Message}"));
+                });
+
                 await _connection.StartAsync();
                 IsConnected = true;
                 Status = new StatusNotice("Connecté au Hub SignalR", StatusSeverity.Info, new RelayCheckCommand("Déconnecter", async () => await DisconnectAsync()));
diff --git a/src/PostIt/PostIt/Views/Chat/ChatPage.axaml b/src/PostIt/PostIt/Views/Chat/ChatPage.axaml
index 55251f544..415b989b1 100644
--- a/src/PostIt/PostIt/Views/Chat/ChatPage.axaml
+++ b/src/PostIt/PostIt/Views/Chat/ChatPage.axaml
@@ -16,7 +16,7 @@
     <vm:ChatViewModel />
   </Design.DataContext>
 
-  <Grid Margin="10" RowDefinitions="Auto, *, Auto">
+  <Grid Margin="10" RowDefinitions="Auto, *, Auto, Auto">
 
     <Grid
       Grid.Row="1"
@@ -71,9 +71,33 @@
         </Grid>
       </Border>
     </Grid>
+    <!--  Saisie et envoi d'un message dans le salon joint  -->
+    <Grid
+      Grid.Row="2"
+      Margin="0,0,0,10"
+      ColumnDefinitions="*, Auto">
+      <TextBox
+        Grid.Column="0"
+        VerticalAlignment="Center"
+        AcceptsReturn="False"
+        IsEnabled="{Binding HasJoinedRoom}"
+        PlaceholderText="Votre message..."
+        Text="{Binding MessageToSend}">
+        <TextBox.KeyBindings>
+          <KeyBinding Command="{Binding SendMessageCommand}" Gesture="Enter" />
+        </TextBox.KeyBindings>
+      </TextBox>
+      <Button
+        Grid.Column="1"
+        Margin="10,0,0,0"
+        VerticalAlignment="Center"
+        Command="{Binding SendMessageCommand}"
+        Content="Envoyer" />
+    </Grid>
+
     <postitControls:StatusBar
       x:Name="StatusBar"
-      Grid.Row="4"
+      Grid.Row="3"
       DataContext="{Binding Status}" />
 
   </Grid>