The painted-houses project has gotten so big that this year, Delphine Buysse, a Belgian curator, has arranged for artists in residence to live at a luxury hotel in Dakar, the Pullman, for a week, while painting in the Médina.

One of the most recent wall paintings was a collaboration between Kouka Ntadi, a Congolese-French artist, and Barkinado Bocoum, a Senegalese artist. Mr. Ntadi painted abstract portraits in black-and-white, and Mr. Bocoum added folksier portraits in bright colors.

Mr. Ntadi loved sharing the neighborhood with the commercial artists of the barbershops and the milk stores.

“I would say there is not really a border between the two in Africa,” he said. “It’s not like in France or the U.S. where there is a snobbism about art, and you can’t be in marketing. So for sure, we can still be an artist and make a design for a bottle of milk or a side of beef.”