Some teenagers and young adults use these expressions to say what's up dude ? :
"Wesh ma gueule, ça va ?" ou "Wesh gros, ça va ou bien?" But it's more between two male friends. Young girls use the term "meuf" meaning woman or femme in verlan, the idiom used when you reverse the place of the syllables in a word to create a brand new one. Like the slang word "mec" (dude in english) for man becomes "keum" in verlan.