My husband and I were amongst the original members of a synagogue that meets in the 17th arrondissement, just a short walk from the Courcelles metro stop. It is small and very welcoming, but as it is 'liberal' -- meaning reform -- it doesn't sound like that is what you are looking for. On the other hand, there are some hotels, restaurants and museums within walking distance. There are also many kind and generous members who would want to help you out.