The French-side lockdown isn't as tight as the Dutch-side. With a permit (derogation certificate) you can move around for specific purposes such as shopping for food, picking up to-go food, exercise (not in groups, 1 hour max, no more than 1km from home), or pet needs. It can be downloaded from the Prefect's office and printed, you can write the entire thing on a piece of paper, or there's a site where you can fill in an electronic copy on your phone. It's good for 1 hour, and the date/time when you left home has to be filled in. The Gendarmes do check certificates, and they are fining violators.