Thank you, I laughed so hard
Now let me clear my throat and switch to French:
Va te faire foutre grosse pute. Je te pisses à la raie [<- my personal favorite], sous-merde. Grosse cochonne. Enculé de pédé de sa mère la pute. Je t'emmerde. Je te nique ta race vieille pédale, nom de dieu de putain de bordel de merde de saloperie de connard d'enculé de ta mère la chienne. T'es con comme un manche, tu pues du cul et ta mère suce comme un aspirateur. Cuve à foutre! Vieille trousse à bite! Je te chies dans l'œsophage! Enfant de viol! Quand ta mère est sorti des chiottes, elle était avec toi! Et appelle-la, que je recommences, tiens! Connard.
;)
Frenchie here, that one got me giggling, well played.
Apparently. However, "You're an idiot as a handle!" may well become my go-to insult...
"Con comme un manche" is stronger than "idiot like a handle" might first seem. Bête is idiot whereas con is etymologically equivalent to cunt. Semantically, however, it conveys something closer to fucking retard. "Asshat", maybe? Too funny. There's nothing funny about having to deal with a con.
Edit: tangentially related, but [0] this prank call is pure comedy and swearing gold. If you speak French and you haven't seen it, you're missing out. If you don't speak French, you get to hear a Corsican accent and Mediterranean rage (starts around 1:25). 10/10.
I think this will, unfortunately, remain comprehensible only to Frenchman!