Bujumbura has a better restaurant scene than its reputation might suggest, with a mix of Burundian, French, and East African options concentrated in the lakeside and central areas.
Au Bon Pain near the central market is the best bet for cheap local food — grilled fish (tilapia and cichlids from the lake), ugali, and beans are the staples. Chez Samy in the Quartier Asiatique has been a reliable upscale option for decades, serving French and Burundian food on a covered terrace. For grilled fish directly by the lake, the informal restaurants at Saga Beach and Karera Beach can't be beaten — cold Primus beer and fresh fish as the sun goes down over Congo.
The main restaurant strip is along Boulevard du Peuple Murundi toward the lake. Most places are open for lunch and dinner; some close on Sundays.