Bruno, do i recall correctly in that you told me you have a copy of AS ARMAS E OS BARÕES by Eduardo Nobre?
If you hit page 121 you will see two sabres in that the hilts visibly resemble the example you posted. Characteristic of Portuguese light cavalry, as per 1806 regulation.
The absence of a prominent pommel is a revealing detail. So is the shape of the langets, an orientalist design bringing memories of Moorish influence. And i wouldn't be surprised that the tang end is screwed to the hilt dome and not peened.
Blades in these swords were sometimes bent to an exagerated point (so called parabolic), a typical period show off fashion, like
IN HERE.
.