germany possible hard lockdown

that's hard to answer - it would depend on exactly the conditions of the lockdown, quarantine for entry from France, etc. You have nearly two weeks - keep watching...

You might check with your airline about rerouting your departure, leaving from Paris. Delta has eliminating fees for rescheduling flights time-wise. I am not sure about changing departure locations.

Gary, Delta has been great about rescheduling but not for changing destinations. Last night I resorted to buying Lufthansa tickets for FRA to Venice and Rome to MCO when Germany became unrealistic.

One does have to wonder how long these shutdowns will keep happening. Makes it difficult to plan going to Europe.
Perhaps I should just forget Europe for a while.

Honestly, for the next month or so I'd stay away from Germany. It looks like more lockdowns will be happening soon. Is there anyway you can change to fly home from France?

I changed my ticket with Delta yesterday. I changed departure destination and dates of travel. Not a problem for me. Since the lockdown in Austria and cancelled Christmas markets in Bavaria, I will be calling them again for another change.