c’est bien ce qui me semblait en relisant l’annonce Amazon:
All Zenith watches sold by Amazon.com are covered by an industry leading limited two-year warranty at no additional cost (see details). Amazon.com in some cases buys watches from authorized dealers, distributors, and other established lines of distribution within the watch industry. In these cases, the manufacturer’s warranty may not apply because we have not purchased the watches directly from the manufacturer. When the manufacturer’s warranty may not be available, Amazon.com offers this warranty for your watch. This applies only to products sold by Amazon.com.
moi qui pensais acheter sur Amazon pour eviter tout probleme de garanti 
merci pour la reponse en tout cas!