Ivory Coast international Nicolas Pepe was at the heart of this 11th league success of the season, scoring in the eighth minute and setting up Rafael Leao and Brazilian Luiz Araujo to complete a cosy win.
Pepe's 13th goal of the campaign drew him level in the Ligue 1 scoring charts with PSG's Kylian Mbappe.
Caen got a late consolation five minutes into time added on from their Chad striker Casimir Ninga.
Lille finished a man down with Zeki Celik's foul on Ninga when the Caen striker was faced with an open goal with seven minutes of regulation time remaining.
Lille took to the pitch in Normandy without France under-21 international left-back Fode Ballo-Toure, who signed for Thierry Henry's strugglers Monaco on Thursday.
The game was moved forward 24 hours as local authorities prepare for the ninth weekend of the 'yellow vest' movement protests.
Lille are now on 37 points, 10 adrift of champions PSG who are at Amiens on Saturday, hoping to bounce back after their shock League Cup loss to Guingamp in midweek.
Also dumped out of the League Cup this week were Lyon, who later Friday were held 1-1 at home by Reims.
Pablo Chavarria put the visitors into the lead in the first half, with Bertrand Traore wrongfooting Reims keeper Edouard Mendy on 70 minutes to level.
Lyon remain in third, four points behind Lille, with a game in hand.