If a compatibility assessment were to be required, it would, according to RATP Dev, be necessary to examine the scheme by the yardstick of Regulation (EEC) No 1191/69 with respect to the subsidies paid before 3 December 2009, the date on which Regulation (EC) No 1370/2007 entered into force.
Par ailleurs, elle précise que l'autorité organisatrice faisait naître des déficits structurels en fixant administrativement les tarifs aux usagers, indépendamment du coût réel de la prestation.