Judgment of the Court (First Chamber) of 27 October 2005 in Joined Cases C-266/04 to C-270/04, C-276/04 and C-321/04 to C-325/04: Reference for a preliminary ruling from the Tribunal des affaires de sécurité sociale de Saint-Étienne: Nazairdis SAS and Others v Caisse nationale de l'organisation autonome d'assurance vieillesse des travailleurs non salariés des professions industrielles et commerciales (Organic) (Concept of aid — Tax assessed on the basis of sales area — Hypothecation of the tax revenue)