How much should I charge?

There are two important issues here:

1) How much are you prepared to work for?

Taking into account transport time and preparation; 30€ / hour does not sound as good when you factor in
- 45 minutes to get to class
- 1h30 class
- then 45 minutes to get to the next class
and therefore brings you just 45€ for 3 hours’ work
or 15€ an hour…
on which you pay tax/social contributions, up to 20-22%

2) What is the going rate?

Consider where you work (Paris, suburbs, 35km from Clermont Ferrand...),
who you work with/teach (language school, retired pharmacist, multinational company, pupil in 6ème...)
and, what you are doing (translation, coaching, general English lessons, specialist lessons...)

As a guideline
- Language schools determine their own rates which are rarely negotiable. It can be anything from 35€/hour to 50€/hour, or more, depending on the type of class and the expertise required.
- A quick survey shows that individual private tuition for children or teenagers in Paris is paid about 25-30€/hour
- Language schools charge companies (as part of the "formation continue") anything from 40€/hour to 70€/hour, or more.