An off-duty FDNY firefighter was arrested Wednesday morning for allegedly assaulting his girlfriend inside her Inwood apartment, police said.

Brian Chevalier, 30, turned himself in to police shortly before 9 a.m. for allegedly knocking his 26-year-old girlfriend to the ground and kicking her around 8 p.m. Sunday inside the apartment in the area of Dyckman and Payson avenues, police said.

Police said children were believed to have been present at the time of the incident.

Chevalier — who sources said is assigned to Engine 95, which is also in Inwood — was charged with assault and acting in a manner injurious to a child. His arraignment is pending in Manhattan court.