Here is the full list of all 12 Monaco: What's Yours is Mine achievements worth 400 gamerscore.
Win an online PvP match
Use C4 to gib three attacking guards simultaneously without dying in single player
Complete Campaign Act I Single Player
Finish any mission in single player with only wrenches
Complete Banque Albert without being seen
Finish The Prison Break with a score under 1:10
Revive an online teammate
Kill everyone in a mission
Play an entire song on the piano with 3 players
Complete Campaign Act II
Complete each mission once without dying
Achieve all four trophies on every solo and co-op mission