Question juridique clé
Whether the cantonal appeal was filed within the ten-day deadline despite mailing from Nice, France.
Solution extraite
The appeal was time-barred because Geneva law required deposit at a Swiss post office; posting in France did not preserve the deadline.
Motifs extraits
The cantonal rule was clear and aimed at avoiding uncertainty about the posting date. Since the envelope showed a deposit in Nice and the postal delivery to Switzerland occurred only after expiry of the period, the deadline lapsed and the appeal became inadmissible.