Here is the full list of all 13 Titeuf: Mega Party achievements.
Complete "Back to School"
Complete "Snow Class"
Change the music of the breakdancer
Get the soccer ball outside the school
Ring for a nurse
Hit the teacher with a paper ball in "Pop Quiz"
Chase after the pigeons near Grandpa
Kick all the Christmas trees
Play and win in "Duels of Death" mode
Unlock all the pranks in "Back to School"
Unlock all the pranks in "Snow Class"
Win "The Duel" 3 - 0
Complete "The School Year"