A srs what said it is a codeshare with Air France.
VS purchased a few pairs of slots from Flybe last year and have leased some of them out to Air France to avoid losing them.
Air France in turn have agreed to a codeshare on the Lyon route. I believe the agreement is for 12 months until VS set up new routes or add to existing routes. The other slots purchased from Flybe are being used for the extra summer services to IAD and BOS.
Regards
Northern Star