diff --git a/applet.cpp b/applet.cpp
index 66f4a3551..02fae784b 100644
--- a/applet.cpp
+++ b/applet.cpp
@@ -759,7 +759,7 @@ KPluginInfo::List Applet::knownApplets(const QString &category,
     return KPluginInfo::fromServices(offers);
 }
 
-KPluginInfo::List Applet::knownAppletsForMimetype(QString mimetype)
+KPluginInfo::List Applet::knownAppletsForMimetype(const QString &mimetype)
 {
     QString constraint = QString("'%1' in [X-Plasma-Mimetypes]").arg(mimetype);
     kDebug() << constraint << endl;
diff --git a/applet.h b/applet.h
index 2195c786c..08f897431 100644
--- a/applet.h
+++ b/applet.h
@@ -244,7 +244,7 @@ class PLASMA_EXPORT Applet : public QObject, public Widget
          *
          * @return list of applets
          **/
-        static KPluginInfo::List knownAppletsForMimetype(QString mimetype);
+        static KPluginInfo::List knownAppletsForMimetype(const QString &mimetype);
 
         /**
          * Returns a list of all the categories used by