Article L2531-17 of the French General Code of Local Authorities
It is instituted an additional tax of 15% to the tourist tax or flat-rate tourist tax collected in the Ile-de-France region by the municipalities mentioned in article L. 2333-26 as well as by the public establishments for intercommunal cooperation mentioned in 1° to 3° of I of Article L. 5211-21. This additional tax is established and collected according to the same procedures as the tax to which it is added….