The exchange sacrifice Rook captures Knight at f3 in the French Defense is close to as frequent as the well known exchange sac Rook captures Knight at c3 in many Sicilian Defenses.
The criterion are can Black damage White’s King side pawn structure and/or win a center pawn allowing his own central e and d pawns to eventually sweep up the board. In the chess position you see, White’s b3 Knight and b5 Bishop are not coordinated properly with White’s other forces.
Also Black’s army is well poised to attack the White Monarch once the single defender of the King is violently removed. Note that after Rf3 and Queen captures at f3, Nxd4 is quite strong attracting the b3 horse away from the protection of the poorly positioned Bishop at d2.
If the g pawn captures the bulldozing Tower, then Qh4 threatening checkmate ain’t too shabby! Note that the lost in space White Prelate at b5 in hopelessly out of play in either an offensive or defensive role.