At Starbucks in Germany, as in the US, the wireless service is provided by T-Mobile/T-Com. The network name (SSID) is different here though: T-Mobile_T-Com.
Devicescape is able to log you in at these hotspots using a variety of T-Mobile/T-Com/T-Online credentials, but be warned you will be paying roaming fees if you are using ones from outside of Germany.
Starbucks in Paris doesn’t have working Wi-Fi yet, though it is clearly on the way. I stopped at two locations near the Les Halles area and both had Wi-Fi hardware running. One had the SSID Starbucks and the other notready – both responded with a page (in English) stating that the wireless network was not available yet.