[Zak]

In the case of Telegram, no selling takes place; the app is free.

I can get the Android version from Google's store, which is uncontroversially subject to German law because Google has physical offices and a financial presence in Germany. I can also download it from telegram.org, which to my knowledge does not have a physical or financial presence in Germany.

Germany probably has the legal authority to order Google to stop distributing the Telegram app and can use that authority to pressure Telegram. What remains unresolved is the degree to which Germany can act against Telegram directly.

[zaarn]

Well, it seems very much like Telegram wants to continue being on the German Play Store. And yes, Telegram is very much selling things, even if the price, at the moment is 0$. They're also going into the ad business, if you check their business web presence.