What is the time line for introducing 3DSv2 in France?

As this is defined by the acquirers' readiness, the availability of 3DSv2 depends on the individual acquirer. 

Most of the French acquirers will support Strong Customer Authentication by September 14th 2019, but not exemptions. The introduction of exemptions will be made available by the individual acquirers between October 2019 and March 2020.