This is a scarce most likely early WW1 era French Military air Service aircraft altimeter barometer made in Paris France. The barometer scale goes from 44-78 torr or mm/gh and the altimeter scale ranges from zero to 4800 m adjusted by knob. The body of the device is very light made of aluminum with minimal wear and tear, the face has nice darker altimeter scale adjusted by a knob. The device comes in an original burgundy velvet and leather case with some of the original cockpit fixing rings. The leather case is missing the front section. The device is still showing differences in the barometric pressure and altitude variation. The initials of the maker are present on the back of the barometer face. Dimensions of the device: diameter 85 mm and 25 mm height. I added a extra picture showing the two early aviation altimeters for comparison.
Excellent piece of early aviation history.