Etienne Lethier is recorded working in Paris circa 1780.
A clock signed Querit, Paris, in a case of closely related design to the present example was sold at Sotheby's, Paris, 15 December 2003, lot 89 (Euro 20,350 with premium). Interestingly that clock retained its original travel case, clearly indicating its purpose.
The term 'pendule portative' does not necessarily describe clocks designed to carry the time from place to place but those that were highly portable. Such clocks were the precursors to pendules d'officier and as with the present example their cases had folding handles; these were usually quite square and sat upon small squat feet, enabling them to work on most surfaces. In Carriage Clocks, Their History and Development Charles Allix and Peter Bonnert observe that in France from about 1775 a succession of attractive small travel clocks appeared and describe this style of clock as pre-pendules de voyage. They illustrate an example (p.21, plate 1/26) by J. B. du Tertre. This has a case with an engraved arched front panel as seen on the present clock.