How to get the start time of the stream (french time)?

You can simply use your favourite Date/Time Library’s function to convert it to any timezone you’d like.

The returned value is always in UTC+0 (currently), so (currently) you’d just need to add 2 hours to it. That obviously changes with Daylight Savings Time, so I highly recommend just using a Date/Time library.

Relevant: https://youtu.be/-5wpm-gesOY