It appears both men were injured and Gabriel went to the hospital and was arrested for battery.
According to TMZ:
The incident happened this morning when Gabriel was dropping Nahla off at Halle's house. Halle was present as were other witnesses when the fight erupted. Sources familiar with the situation tell TMZ ... "Gabriel went nuts" and started fighting Olivier. Olivier was not taken to the hospital. It appears he won the fight -- but he did suffer injuries.Sources close to the investigation tell TMZ, Olivier wants to press charges.
Halle Berry and Gabriel Aubry have had quite a tumultuous relationship since the ugly custody battle over their daughter, Nahla began and it looks like the tension among the family has reached an all time high.