On 12th July 1790,, just after the French Revolution, the, French National Assembly signed the Civil Constitution of the Clergy. This bill required all priests to swear allegience to the nation, above all other authority. This meant Rome and the Pope and, would certainly result, in excommunication of those who signed. The French priests were forced into an impossible position and strongly divided. Many refused to sign, either fleeing or remaining to incite counter-revolution among the peasantry in already largely royalist regions like the Vendée and Brittany. When the pressure became unbearable in August 1792, De Chanterac, accompanied by a group of some 20 priests from the Alet region fled to Spain. Among them was Antoine Bigou, priest of Rennes-le-Château. Other priests from the area of whom their presence in Spain has been documented include L. Raynaud, F. Ginette, J. Loubet and G. Cairol.
De Chanterac died in the Spanish town of Sabadell during his voluntary exile on 27th April 1793 at the age of 70. He lies buried in the Church of Sabadell.