diff --git a/injection/_core/module.py b/injection/_core/module.py
index ffa688a..04c291c 100644
--- a/injection/_core/module.py
+++ b/injection/_core/module.py
@@ -156,6 +156,12 @@ def __str__(self) -> str:
         )
 
 
+@dataclass(frozen=True, slots=True)
+class UnlockCalled(Event):
+    def __str__(self) -> str:
+        return "An `unlock` method has been called."
+
+
 """
 Broker
 """
@@ -802,8 +808,11 @@ def change_priority(self, module: Module, priority: Priority | PriorityStr) -> S
         return self
 
     def unlock(self) -> Self:
-        for broker in self.__brokers:
-            broker.unlock()
+        event = UnlockCalled()
+
+        with self.dispatch(event, lock_bypass=True):
+            for broker in self.__brokers:
+                broker.unlock()
 
         return self
 
@@ -838,20 +847,20 @@ def remove_listener(self, listener: EventListener) -> Self:
         self.__channel.remove_listener(listener)
         return self
 
-    def on_event(self, event: Event, /) -> ContextManager[None] | None:
+    def on_event(self, event: Event, /) -> ContextManager[None]:
         self_event = ModuleEventProxy(self, event)
         return self.dispatch(self_event)
 
     @contextmanager
-    def dispatch(self, event: Event) -> Iterator[None]:
-        self.__check_locking()
+    def dispatch(self, event: Event, *, lock_bypass: bool = False) -> Iterator[None]:
+        if not lock_bypass:
+            self.__check_locking()
 
         with self.__channel.dispatch(event):
             try:
                 yield
             finally:
-                message = str(event)
-                self.__debug(message)
+                self.__debug(event)
 
     def __debug(self, message: object) -> None:
         for logger in self.__loggers:
diff --git a/tests/core/test_module.py b/tests/core/test_module.py
index 532c422..eb15436 100644
--- a/tests/core/test_module.py
+++ b/tests/core/test_module.py
@@ -405,6 +405,22 @@ class C(A): ...
         assert isinstance(b1.a, A)
         assert isinstance(b2.a, C)
 
+    def test_unlock_with_module_in_use_raise_module_lock_error(self, module):
+        second_module = Module()
+        module.use(second_module)
+
+        @module.singleton
+        class A: ...
+
+        @second_module.singleton
+        class B: ...
+
+        module.get_instance(A)
+        second_module.get_instance(B)
+
+        with pytest.raises(ModuleLockError):
+            second_module.unlock()
+
     def test_unlock_with_scoped_dependency(self, module):
         @module.scoped("test")
         class Dependency: ...