Nouns ending in -at are masculine.
The suffix often marks a status or condition.
Is chocolat masculine or feminine?
lechocolat
The rule behind it
100% of -at nouns are masculine
In context
Ne songe même pas à manger mon chocolat !
Don't you even think of eating my chocolate!
Quoi ? ! T'as mangé mon ours en chocolat ? !
What?! You ate my chocolate bear?!
Quelques camarades me virent lui donner du chocolat.
Some classmates saw me give him chocolate.