The portal is translated using lit-localize. The texts of the base language (German) are contained in the source files. The other languages (currently only French) can be translated using a XLIFF file.
Make sure to pull the latest changes:
git pull --rebase
Update the French translation file by extracting the German texts from the source files:
npm run locale:extract
The generated translation file xliff/fr-CH.xlf can then be edited manually with a text editor or more conveniently with a XLIFF-compatible editor like Poedit (open source).
When all texts are translated, generate the locale artifacts:
npm run locale:build
Then commit & push the changes:
git commit -m 'Update french translations'
git push