Nico,
As Andrew stated, the founding users of FQF are the local manufactures but unlike the Geneva Seal, the FQF is open to brands outside the Canton. It is not restricted by geography.
The main restriction is the high failure rate and the need to engineer your watch to survive the tests.
Most brands even with Geneva Seal will not dare to attempt a FQF certificate.
Even from the Fleurier brands, Chopard has the vast majority of successful certifications. In fact, I don't recall Bovet having passed any test. There was a "limited edition" Parmigiani FQF announced but I have not seen any watch "in the field".
Chopard has the QF versions of their XP and Tourbillon watches. As an example of the severity of the FQF, the watches that pass Geneva Seal may not pass the FQF. Chopard had to re-engineer their watches to achieve FQF and even have a triple-certified Tourbillon with COSC, Geneva Seal and FQF. That, my firend, is the ultimate cerified watch!
Regards,
MTF