Small black shoulder bag by french designer jean colonna (c. 1990s). Made from a soft + supple leather, it is essentially one long tube folded in half, with zipped compartments at each end (things can additionally be put into the tube, which has a press stud closure, although this section likely best for papers / things that won't fall out). Long strap (in addition to short carrying handle) allows the bag to be worn cross body or off one shoulder.

Height (folded): 20 cm
Height (unfolded): 39 cm
Width: 18.5 cm
Depth: 3 cm
Handle length: 12 cm
Strap length: 106.5 cm

Leather outer, (presumed) nylon handle