If you need a culture fix the Palais des Beaux Arts is world class. As is La Piscine in Roubaix. If you have time and transport, the Louvre-Lens (in Lens, an old mining town, south of Lille) is amazing. Really. The LaM (Lille Métropole Musée d’art moderne, d’art contemporain et d’art brut) is great.
Villa Cavrois, halfway between Lille and Roubaix, is an Art Deco masterpiece. If you stand looking at the Le Moulin d’Or bar on Place Theatre, you can see cannonballs embedded in the walls, from some long-ago siege. Close by, the old stock exchange (La Vieille Bourse) now houses a well-known second-hand book market.
If you want to do a nice walk to clear your heads (!) the area around the Citadel (an old Vauban-built military base still used by the French military) is your place! There are lots of bars and restaurants dotted along the various waterways. Also, a small zoo.
There are a few cinemas. The UGC on Rue de Béthune is best for VOSTF (Version Originale Sous-Titres Français).
You’re obviously very close to lots of The Western Front. To the north, Ypres is a good starting point; the Last Post ceremony at the Menin Gate each evening is very moving. Too many sites to mention, many of them unforgettable. South you get to places like Vimy Ridge, Notre Dame de Lorette/Ring of Remembrance. CWGC graveyards everywhere. If you head to The Somme, find the road from Peronne to Albert, there are dozens of things to see. There’s quite a large CWGC cemetery in the Lille Sud cemetery.
If you’re staying a few days and have transport, other places worth a visit include Arras, Cassell (lovely hilltop town, rumoured to be on the hill that the Grand Old Duke of York marched his men up and down!). Tournai, nice Belgian town. Further afield: Ghent, Bruges, Antwerp are not far. The Waterloo Battlefield is just over an hour away, as is Agincourt (both have museums and various places to visit). There’s a mining museum in Lewarde (https://www.chm-lewarde.com/en/).
Lille RWC Guide 