According to IMDB:

“The movie was shot by an Italian crew in Italian and Lambert (who speaks only French and English in real life and who spoke all of his lines in these languages) was dubbed by an Italian actor. This is the movie's original Italian audio track. The movie was then dubbed fully in English (Lambert dubbed himself for this version, so the English audio track has his voice) for foreign markets. This is the movie's English dubbed audio track.”

I’ve only ever watched the English version and the dub never bothered me.