The fast way, if you can get and use Kindle for PC 1.17.1 (on filehippo, for instance), is to use that. It will download books in the traditional (usually encr

The fast way, if you can get and use Kindle for PC 1.17.1 (on filehippo, for instance), is to use that. It will download books in the traditional (usually encrypted) azw/mobi formats, which you can drag right into calibre (with the dedrm plugin). Newer KindlePC versions (1.19 and up) tend to download books in kfx format, which doesn't currently have a dedrm plugin. All kindle installers should be signed by Amazon Services, so it shouldn't be a problem getting them from a third party as long as you check the signature. Alternatively, on the [kindle] "content and devices" webpage, if you click the three dots in the second column (I'm guessing the interface is the same for the french website), it gives you the option to individually download & transfer books via usb if you have a kindle registered to the account. If you have calibre and the apprenticealf dedrm plugin, I believe that process still works, though I haven't tried for a long time.