New york market: USD/EUR =7.0800.

Paris market: GBP/EUR =9.6530.

Then GBP/USD (two cities) = GBP/EUR divided by USD/EUR = 9.6530/7.0800 = 1.3634 can be converted from two markets.

London market, GBP/USD =1.4325; GBP/USD (two cities) =1.3634; The price difference of 0.069 1 is very large and can be arbitrage.

But in general, the actual quotation price difference should be less than 0.000 1, so there will be no such big price difference (plus the handling fee, there is no profit at all), so there is basically no arbitrage opportunity in actual operation.