Video of the incident showed Brashear punching opponent Gaby Roch in the back of the head from behind, touching off a bench-clearing brawl between his Riviere-du-Loup 3L and the visiting Jonquiere Marquis.
The league, which translates as North American Hockey League but is not related to a circuit of that name based in the United States, is known for highlighting fights.
Brashear, 41, joined the league after his NHL career ended in 2010.
He had 85 goals in 1,025 career games for Montreal, Vancouver, Philadelphia, Washington and the New York Rangers. His 2,634 penalty minutes ranks 15th all-time.