The decision follows a ruling by the European Commission in June that the French government must open Orly to foreign carriers.
British Midland said the Orly service would include a summer leisure return-flight price of 81 until the end of October. The offer has already been running on existing flights to Charles de Gaulle airport in Paris.
The company said there was strong demand from its customers for more frequent flights to Paris Orly is popular because it gives easier access to the south of the French capital. It also allows easier connections for onward travel, including to holiday destinations in the south of France. The company has no plans to cut any of its eight existing return services which operate daily between Heathrow and Charles de Gaulle.
British Airways has already started four daily return flights between London and Orly, two of which are operated by its French affiliate, TAT.
The French government has been limiting foreign carriers to four return Orly flights a day but has agreed to lift this restriction as part of a package under which the European Commission has approved 2.3bn in state aid for Air France. BA and British Midland argue that state aid should be banned and that free access to Orly is rightfully theirs.
The British airlines are still considering whether to take the Air France case to the European Court of Justice, which they may do with other European airlines.Reuse content