could someone suggest me some nice french movies with clear dialogues for beginers?
I like "Un Monstre à Paris". It is an animation movie so the dialogues are much clearer than of those real people acting. I don't know your taste but I hope you find it enjoyable!
I like the Jean Cocteau version of "La Belle et la Bête" from 1946. It was the first movie I ever saw in French; our first-year teacher showed it to us. The dialogue is fairly basic, it contains very little if any slang, the actors speak reasonably clearly, and almost everyone knows the story so it's pretty easy to follow.