Sorry, that was the wrong url.
www.give-consulting.com/index.php/de/fue...rojektanfragen/34313
www.give-consulting.com/index.php/de/fue...rojektanfragen/34321
But now I understand - the first url leads to .../de/...
The second to .../en/...
So the urls change only if I change the language, although it leads to the same article.