Even with the long straight lugs, it fits your wrist perfectly so I am guessing that the watch is between 35mm and 36mm. I only wish Breguet made more watches in this size.
It was about 20 years ago when I became interested in mechanical watches and discovered the wide use of the JLC. 889 family in high quality pieces. This Breguet is a fine example of an elegant watch using one of my favorite movements.