From July 1st 2015 to June 30th 2016, the citizens of France visitors will not need a visa to Vietnam for less than 15 days of stay (more about Vietnam visa exemption). For those who make a plan to stay in Vietnam for a short time (less than 15 days) and do not re-turn to the country before going back home, that is no problem. However, if you schedule a long trip with the return to Vietnam after 1 or 2 weeks, you should give careful consideration to the visa requirement then.
According to the Article 20 of the Vietnam Law on Immigration No. 47/2014/QH13, visa waiver citizens must wait for 30 days from the previous entry to take advantage of a next exempted entry visa, otherwise, they must apply for a visa for their return. The French tourists may be denied to enter Vietnam if the gap between 2 entries is less than 30 days and have no visa in hand before boarding the flight return to Vietnam.
In this case, you should apply for Vietnam visa on arrival for the second entry before departure. You can enter Vietnam with visa free for 15 days first and enter with visa on arrival later. Many French have to change the flight, or employ emergency visa service at the last minutes due to having no visa for the 2nd entry.
We can help you with the emergency visa service to provide the approval letter in 2 working hours. Please take our online supports by calling +84.912.685.141 or emailing us to vietnamvisabooking@gmail.com