The French franc and the Irish pound may be irrevocably linked at the rate of 8.32894 francs to the pound, but the money-changer in the Rue du Four is offering only 8 francs to the pound - 800 francs for £100, 4,000 francs for £500 or 8,000 francs for £1,000, with no commission.

When I protested that he was not complying with the fixed exchange rate, wherein the franc and the pound are now part of the same currency, the money-changer held up a copy of the financial daily La Tribune. "The money-changers are still waiting for the rules," the headline said. "You're better off here than at the bank," he explained. "They're charging 20 francs in commission, plus 2 per cent of the amount changed".

The nearby Societe Generale branch revealed the money-changer had underestimated the retail banks' greed.

The Societe Generale, one of the top French banks, offers 832.89 francs for £100, 4,164.47 francs for £500 or 8,328.94 francs for £1,000 - but there is a minimum commission of 50 francs on every operation, plus 3.5 per cent of the amount changed.

"Before, we made money on the difference between the buying and selling rates," the head of the exchange department said. "We didn't need to charge a commission."

From behind the bullet-proof glass of his small cage on the pavement, the moneychanger complained that "the little guy is getting hurt".

He sells all of his foreign currency to two specialist banks, the CPR and Inchauspe. Instead of purchasing the 11 euro currencies from him at a flat rate, as they used to, the wholesale exchange banks this week began charging a commission of 70 centimes on the equivalent of between 20,000 francs and 50,000 francs, and slightly smaller commissions thereafter. The Banque de France reportedly changes banknotes from the euro zone for free, and the ministry of finance is allegedly considering regulations, but in the meantime French money-changers and commercial banks appear determined to earn as much as they can.