Validity and efficacy of the arbitration agreement entered into prior to the Brazilian Arbitration Act and set forth in an international bidding notice governed by Decree-Law No. 2.300/86, which resulted in an administrative contract executed by the Companhia de Saneamento do Distrito Federal – CAESB with a Brazilian construction company. A disagreement involving findings made by an audit of the Tribunal de Contas does not interfere with the choice made for dispute resolution and, therefore, with the validity of the arbitration agreement. The disagreement between payments made and the amount actually owed qualifies the contractual controversy to be resolved in arbitration: