No, this is currently not possible and I think - if possible at all - it will take a long time.
Personally I think the focus right now should be better support of languages other than English. Looking at translate.mycroft.ai there is only German with a 100% translation rate, runner-ups are Spanish (92%), Portuguese (86%) and Italian (85%), followed by Dutch (64%) - still a long way to go…
As Dominik said this isn’t supported functionality, and multilingual use isn’t a priority for us at the moment.
If you wanted to hack it together, I assume the simplest version of this would be to include the French answers in the German language files and vice-versa. However I’m not sure how well a German TTS would pronounce the French terms. So you’d need to either regularly switch TTS configurations or run both simultaneously.
I’d be interested to hear how it goes if you give it a try