Fosca's studio is the greatest value for money you can find in the St Germain area. Tiny as a Parisian studio tends to be, yet it has everything you need for your stay, including a fully equipped kitchen if you're the type who likes to cook whilst on the road. Very well connected with metro and RER, super central. Check-in and check-out are flexible and simple, and during your stay, you have the keys to the studio, which is entirely independent. I used to prefer hotels but thanks to places like this one, I am more and more often using airBnB when traveling.