The Louvre-Lens museum opened on December 12th, 2012 in Lens, a former mining town in north France which has seen better days. It's a huge, typically grand French project, aiming to both bring high culture to this part of provincial France, and at the same time, give the local economy a boost that, the authorities hope, will transform the area. If it worked in Metz with the Pompidou Center, why not in Lens?
That remains to be seen, but in the meantime, the new museum makes a pretty good reason to visit north France. The building itself of glass and aluminum is impressive, though the surrounding park is in its infancy. Enter the exhibition (which is free), and you're faced with an extraordinarily rich collection of art - from the beginning of writing - that is 3,500 BC to the mid-19th century. Masterpieces from different eras and different cultures, all freestanding, fill the enormous space. It's pretty show-stopping. There's also an important temporary exhibition on the Renaissance (admission is 9 euros), so if you can, make it for half a day. All the exhibits in the main gallery are from the Louvre and will change every five years (with 20% changing each year). The temporary exhibitions will borrow more from other sources.
It's easy to get to, with good connections from Lille. If you're coming from the U.K., you could do it in a day, but I'd advise staying in Lille or somewhere in the area and combining it with visits to the nearby World War I memorials, and some of the delightful towns which make such a good short break.