diff --git a/autotests/addresstest.h b/autotests/addresstest.h
--- a/autotests/addresstest.h
+++ b/autotests/addresstest.h
@@ -42,6 +42,7 @@
     void shouldParseAddressVCard4();
     void shouldExportVCard4WithGeoPosition();
     void shouldParseAddressVCard4WithGeoPosition();
+    void countryToISOTest();
 };
 
 #endif
diff --git a/autotests/addresstest.cpp b/autotests/addresstest.cpp
--- a/autotests/addresstest.cpp
+++ b/autotests/addresstest.cpp
@@ -426,3 +426,13 @@
                         "END:VCARD\r\n\r\n");
     QCOMPARE(ba, expected);
 }
+
+void AddressTest::countryToISOTest()
+{
+    using namespace KContacts;
+    QCOMPARE(Address::countryToISO(QStringLiteral("France")), QLatin1String("fr"));
+    QCOMPARE(Address::countryToISO(QStringLiteral("Frankreich")), QLatin1String("fr"));
+    QCOMPARE(Address::countryToISO(QStringLiteral("Germany")), QLatin1String("de"));
+    QCOMPARE(Address::countryToISO(QStringLiteral("Österreich")), QLatin1String("at"));
+    QCOMPARE(Address::countryToISO(QStringLiteral("Disneyland")), QString());
+}
diff --git a/src/address.h b/src/address.h
--- a/src/address.h
+++ b/src/address.h
@@ -303,10 +303,10 @@
 
     /**
       Returns ISO code for a localized country name. Only localized country
-      names will be understood. This might be replaced by a KLocale method in
-      the future.
+      names will be understood.
       @param cname  name of the country
-      @return       two digit ISO code
+      @return       two digit ISO code, empty string if the country was not
+                    recognized
     */
     static QString countryToISO(const QString &cname);
 
diff --git a/src/address.cpp b/src/address.cpp
--- a/src/address.cpp
+++ b/src/address.cpp
@@ -672,10 +672,7 @@
         file.close();
     }
 
-    // fall back to system country
-    QString systemCountry = QLocale().bcp47Name();
-    sISOMap->insert(cname, systemCountry);
-    return systemCountry;
+    return {};
 }
 
 QString Address::ISOtoCountry(const QString &ISOname)