[2] His greatest achievement was winning the 1903 Paris-Madrid race, which was stopped at Bordeaux because of the number of fatalities on the primitive French roads.

With starting number 168, Gabriel was not one of the first hundred starters,[3] yet he was the third to arrive at Bordeaux, and a clear leader when times were taken into account; the stopping of the race meant he was the winner by default.

[4] Probably as a result of this performance, he was chosen to represent France in the 1903 Gordon Bennett Cup at Athy in Ireland, and finished 4th, despite his Mors suffering a misfire and giving away a significant amount of power to the winning Mercedes.

[5] Gabriel was meant to have the honour of being the first starter at the first Grand Prix, the 1906 Grand Prix de l'ACF, being part of the de Diétrich team which had drawn start number 1, and being the leading driver; however the engine stalled at the start and he was the second car away.

[9] Gabriel was married twice; firstly, to Berthe Cerisay in 1901 in Paris, and the second time to Huguette Detrez in Colombes in 1938.