Facts
The Aluminium Industry Corporation (AIAG) concluded concession contracts with the Valais municipalities of Saint-Martin, Hérémence, Mase and Vernamiège in 1905 for the use of the hydroelectric power of the Borgne river. These contracts had a duration of 99 years and set the annual fee at 1 franc per effective horsepower used. According to the 1898 cantonal law, these fees were subject to revision every ten years. The municipalities requested the revision of the fees for the period 1956-1965. The Cantonal Tribunal granted their requests and set the fee at 4.50 francs per effective horsepower, instead of the initial 1 franc and 2 francs since 1916. AIAG filed an administrative appeal against these decisions with the Federal Tribunal.Considerations
1. The Federal Tribunal first confirmed its jurisdiction to rule on these appeals, pursuant to Articles 71 and 74 of the Federal Law on the Utilization of Hydroelectric Power (LUFH). 2. On the merits, the Federal Tribunal ruled that the decennial revision of the fees provided for by the 1898 cantonal law (taken up in the 1957 law) was a mandatory legal rule that also applied to municipal concessions, despite the clauses in the concession deeds setting a maximum amount of 2 francs per effective horsepower. These clauses could not prevent the revision, which aims to maintain the real value of the fee and does not infringe on the…