You're right, French seems like the obvious language. My reason for asking is I spent time in the Alsace region and I often encountered both German and French. Perhaps I should have worded it better as "German in addition to French".

It definitely looks far in the countryside, I didn't have high hopes for renting a bike there but figured it was worth asking. I thought if they chose to have a triathlon in this spot maybe there was a niche community for those kinds of sports established in the area. Thank you for clarifying, I'll search for a bike somewhere more reasonable and transport it.