diff --git a/effects.cpp b/effects.cpp
--- a/effects.cpp
+++ b/effects.cpp
@@ -250,6 +250,9 @@
     connect(c, &AbstractClient::windowClosed, this, &EffectsHandlerImpl::slotWindowClosed);
     connect(c, static_cast<void (AbstractClient::*)(KWin::AbstractClient*, MaximizeMode)>(&AbstractClient::clientMaximizedStateChanged),
             this, &EffectsHandlerImpl::slotClientMaximized);
+    connect(c, &AbstractClient::fullScreenChanged, this, [this, c] {
+        emit windowFullScreenChanged(c->effectWindow(), c->isFullScreen());
+    });
     connect(c, &AbstractClient::clientStartUserMovedResized, this,
         [this](AbstractClient *c) {
             emit windowStartUserMovedResized(c->effectWindow());
diff --git a/effects/maximize/package/contents/code/maximize.js b/effects/maximize/package/contents/code/maximize.js
--- a/effects/maximize/package/contents/code/maximize.js
+++ b/effects/maximize/package/contents/code/maximize.js
@@ -93,6 +93,7 @@
         effect.configChanged.connect(maximizeEffect.loadConfig);
         effects.windowGeometryShapeChanged.connect(maximizeEffect.geometryChange);
         effects.windowMaximizedStateChanged.connect(maximizeEffect.maximizeChanged);
+        effects.windowFullScreenChanged.connect(maximizeEffect.maximizeChanged);
     }
 };
 maximizeEffect.init();
diff --git a/libkwineffects/kwineffects.h b/libkwineffects/kwineffects.h
--- a/libkwineffects/kwineffects.h
+++ b/libkwineffects/kwineffects.h
@@ -1442,6 +1442,13 @@
      **/
     void windowMaximizedStateChanged(KWin::EffectWindow *w, bool horizontal, bool vertical);
     /**
+     * Signal emitted when the full screen state of the window @p w changed.
+     * @param w The window whose full screen state changed
+     * @param fullScreen Whether the window is full screened
+     * @since 5.11
+     **/
+    void windowFullScreenChanged(KWin::EffectWindow *w, bool fullScreen);
+    /**
      * Signal emitted when the geometry or shape of a window changed.
      * This is caused if the window changes geometry without user interaction.
      * E.g. the decoration is changed. This is in opposite to windowUserMovedResized