Flight with short layover (less than 3 hours)
Example 1: Marseille -> Paris Roissy Charles de Gaule -> New-York.
Example 2: Marseille -> Amsterdam -> New-York.
Example 3: Paris Roissy Charles de Gaule -> Amsterdam -> New-York
=> validation at the departure airport (Marseille).
Flight with long layover (more than de 3 hours)
Layover in the country of departure (example: Marseille -> Paris Roissy Charles de Gaule -> New-York) -> validation à the airport of layover (Paris Roissy Charles de Gaule).
Layover in another EU country (example: Marseille -> Amsterdam -> New-York)
Chek-in of items in hold luggage at departure airport:
Check-in to final destination (New-York) -> validation at the departure airport (Marseille).
Check-in to the destination of layover (Amsterdam) followed by a second check-in at the destination of layover (Amsterdam) -> validation at the airport of layover (Amsterdam).
Check-in of items in hand luggage at departure airport:
Access to the customs desk at the airport of layover -> validation at the airport of layover (Amsterdam).
No access to the customs desk at the airport of layover -> validation at airport of departure (Marseille).
Note:
Even if you have a flight with a long layover (more than 3 hours), we advise you to make an initial validation attempt at the departure airport.
At some airports (Paris Roissy Charles de Gaule), validation at the airport of departure will require you to temporarily leave the “landside” zone to have access to the customs desk in the “airside” zone.
See also question: