IAG's low-cost long-haul airline Level will base two aircraft at Paris Orly airport, its second base since launching last year.
"We are delighted to launch flights from our second European city with four exciting new routes," IAG's chief executive Willie Walsh said.
Walsh said he expects Barcelona-based Level to be profitable this year.
It will operate five aircraft in 2018 including two Airbus A330-200 aircraft based at Orly flying routes to Montreal, NewYork, Guadeloupe and Martinique beginning next July.
One-wayfares will start from €99.
Level flights from Paris Orly will be operated by staff who currently work for OpenSkies, IAG's French airline, which will cease to operate at the end of next summer.
OpenSkies staff will then solely operate Level flights.