The Brussels Cinema days festival is taking place this week, hosted at BOZAR. This festival has many interesting films to choose from. I would propose this time a debut film feature by the Finish director, Juho Kuosmanen, which won the top prize in the Un Certain Regard section at this year's Cannes. It has been described as a funny, forlorn, and irresistibly charming film, shot in black and white, and with great attention to the 1960s period detail.
A good review is provided here.
Since this is a one-off film screening, part of a popular festival, I would advise you to buy your tickets in advance (online or at the venue). By the way, you can also get a pass for €20 allowing access to 5 films of your choice.