Wolves Don't Prey on Wolves

Two wolves in lawyer’s robes are congratulating each other in front of an eating place serving cold food.

The caption reads in the original French: Les loups ne se mangent pas (entre eux). This proverb doesn’t seem to have any satisfactory equivalent in English. It is used to signify that members of a given group will readily seek victims outside the group, but won’t try to harm or take advantage of each other. "Birds of a feather flock together" might provide a loose approximation, in its more negative implications.