The seven-times French champions went to 25 points, one ahead of Girondins Bordeaux, who moved up to second after they beat a depleted Olympique Marseille 1-0.
Marseille are fourth on 23, tied on points with Paris Saint-Germain who lost 2-1 at home to nine-man Stade Rennes on Saturday, but behind on goal difference.
"I do not know for how long we will stay atop, if it will be two hours, two days, two weeks or two months," Lyon coach Remi Garde told a news conference.
"There is no point in hiding our ambitions or delight being top at the moment."
"But I prefer when we are here because it brings confidence. We just enjoy being there. We will keep the top spot if we deserve it."
Lyon dominated possession throughout the first half but failed to create clear-cut chances and were condemned to harmless long-range efforts.
They broke the deadlock on the stroke of half-time after a great Anthony Reveillere effort in the box prompted centre back Weber to accidentally poke the ball into his own net.
Lyon kept control of the game after the break, without really threatening goalkeeper Kossi Agassa.
Bafetimbi Gomis, who handed France a 2-1 victory in Italy in their friendly on Wednesday, eventually doubled the lead with 17 minutes to go with a powerful volley after a Steed Malbranque cross had hit the crossbar. Lisandro Lopez wrapped it up late on. Reims are 13th on 15.
Yoan Gouffran's fourth goal in as many league games proved enough for Bordeaux to humble Marseille.
Bordeaux dominated the game and went the closest to opening the scoring in the 35th when Marseilles full-back Jeremy Morel saved a Henri Saivet header on the goal-line.
Gouffran tapped in a Benoit Tremoulinas pass in the 52nd minute to extend Bordeaux's successful home run against opponents who have not won there since 1977.
The decimated visitors finished the match with a strike partnership of prospect Bilel Omrani, who had played eight minutes in Ligue 1 before this game, and a 27-year-old amateur, Fabrice Apruzesse, who had never previously featured in the first squad.
Defender Lucas Mendes dismissal in stoppage time added to Marseille woes.
Nice clinched a 1-0 home victory against Toulouse thanks to a second-half goal by striker Dario Cvitanich.
They climbed to 11th on 16 points while Toulouse, who have lost for the fourth consecutive time in all competitions, stay ninth on 19.
