Ryanair today threatened to close its base in the southern French city of Marseille in January after French prosecutors refused to drop a case against the airline.
Prosecutors have accused Ryanair of illegal working practices after the airline declared 200 employees in France as working in Ireland.
In May, Michael O'Leary threatened to pull out of the city and relocate the operation outside France if the case went ahead.
The Ryanair boss said the jobs are "Irish jobs on Irish aircraft...defined by EU regulations as Irish territory".
The jobs will move to other bases in Spain, Italy and Lithuania, but a spokesman for the company could not confirm if there would be any job losses as yet.
"We are very disappointed at this decision by the French authorities to initiate proceedings against Ryanair’s base in Marseille, which complies fully with EU regulations for mobile transport workers," said Ryanair boss Michael O’Leary.
"These are not French jobs, but rather Irish jobs on Irish aircraft, which are defined by EU regulations as Irish territory. All of these people pay their tax and social insurance, in accordance with EU regulations, in Ireland and they remain fully tax compliant.
"Sadly the loss of these 4 aircraft, 200 jobs and 13 routes at Marseille is the high price necessary to demonstrate that these are mobile Irish workers, which is why they are covered by the EU regulations for mobile transport workers; and not by a local French decree which Ryanair is currently appealing to the European Courts.
"This ill-judged legal action has therefore cost Marseille and France jobs, foreign investment and lost visitors in circumstances where our Marseille base fully complies with EU regulations for transport workers."