This is by far and away the clearest explanation I have encountered of the entire situation:

https://www.easyship.com/blog/de-minimis-exemption-suspension

As I understand it, you have two options at this point. First, simply await La Poste's solution to the matter. In a thread below, I found Royal Mail is setting up a Delivery Duty Paid system which will comply with all this. I imagine La Poste will probably follow at some point. I think Norway's postal system's language on this issue indicated an intent to also set this up. There are some nations' postal services which seem willing to do this. That could take quite a lot of time, probably months.

Your second option will be to shop for a common carrier service...UPS, FedEx, or the like. They already have the tools in place to be compliant with these rules, and will work with you to select the service which best suits your shipping needs. They will be more expensive than any postal service, however after those postal services which choose to become compliant actually do so, their services probably won't be too much cheaper.

Hope this is helpful. Good luck to you. I am at least one US resident who fully understands. You'll be "ready when you're ready." Will need to be sorted out.