You choose the one single example where this doesn't apply: If you mail any letter from Germany to anywhere else, don’t just use a regular stamp (0,80€) but use

You choose the one single example where this doesn't apply: If you mail any letter from Germany to anywhere else, don’t just use a regular stamp (0,80€) but use certified mail (between 3 and 4€) and you’ll have a tracking code, and it’ll arrive in france within of 24h (because then it’ll just be delivered as parcel by DHL, which is owned by the german mail service)