Fabian Ruiz's brilliant strike was sandwiched between those two goals as the defending French champion remained perfect, leapfrogging Marseille and Monaco after their wins earlier in the day.

Romain Del Castillo had put Brest in front with a penalty just before the half-hour mark after a foul by Nuno Mendes on Ludovic Ajorque.

PSG then equalised in the 42nd minute with a header from the unmarked Dembele off Marco Asensio's pinpoint cross.

Brest offered little in the second half despite PSG taking its foot off the gas, but Fabian put the hosts in front in the 73rd minute with a superb long-range effort.

Just 80 seconds later, Dembele sealed the points with his second, pouncing on a loose ball after a counter-attack.