About halfway through the film, I realized that I knew almost nothing about the country of Senegal, except that it used to be a French colony, so I paused the film to do some reading about the country. I learned many interesting things, but the most interesting (to me) was that Senegal didn't become an independent nation until 1960, which means that, when Ousmane Sembene released his film, Senegal had only been independent for six years.
As I resumed watching the film, this context proved helpful in trying to understand it. The plot is fairly straightforward. A young black woman named Diouana is hired by a white French couple in Senegal to take care of their children. When the couple moves back to France, they send for the girl to come live with them. However, once she arrives, the white French woman expects Diouana to be a subservient house-maid, and treats her badly. Ultimately, Diouana commits suicide.
The film, I think, is about the enduring legacy of colonialism and racism, even after independence. These things have a long history, and people who have lived with certain ideas and attitudes can't just shut them off just because a new law passes, or a new constitution is created. The film shows the human element of these abstract ideas. While it is certainly a tragedy, it prompts the viewer to think about deep things, which is what tragedy is supposed to do.
The film looks like a French New Wave film, in black and white, with lots of handheld shots. It's a very cool-looking film, despite the heavy subject matter. I look forward to watching more films by Ousmane Sembene. Here's a trailer for "La Noire de..."
And here's an interesting and informative video I found about Senegal: