Note: I’m slipping! I initially identified this as one of the mystery Chinese pistols, having not recognized it as a Bernardon-Martin. A bunch of folks in the comments did, though, and I have corrected the post.
A reader named Liliang sent me these photos of a pistol from a Chinese museum (the specific museum or its location was not mentioned). It is a Bernardon-Martin model 1909, although the exact details don’t quite fit any of the variation I can find documented.