The Palais des Beaux-Arts is Lille's great secret and, for most visitors, its greatest surprise. After the Louvre, it is the largest and finest art museum in France — a claim that sounds implausible until you are standing inside looking at Rubens, Van Dyck, Goya, Delacroix, and Courbet arranged in handsome 19th-century galleries with no discernible crowd. The collection is exceptional in breadth: Flemish and Dutch masters from the 16th and 17th centuries, French academic painting, a superb medieval sculpture gallery, and a basement dedicated to ceramics, coins, and archaeological finds from the region.
The real revelations are in the drawings room: two Raphael drawings, acquired by the city in 1803, sit in a climate-controlled case surrounded by works on paper of comparable quality. Upstairs, the Delacroix collection is one of the finest outside Paris, and the small room dedicated to Courbet's paintings of the sea is unexpectedly moving.
Entry is paid but very reasonable; the first Sunday of each month is free. Closed Tuesdays. Allow two to three hours to do it justice, though you could spend an entire day.