Staff who work for the FIA are in the privileged position of learning information from all teams on the grid and, as a result, a 12-month gardening leave period was agreed upon for any FIA member joining any team in future.
But Mekies, as it currently stands will be able to start work for Ferrari in September, serving just six months of gardening leave just like Marcin Budkowski did before joining Renault this season.
The appointment has caused a new wave of anger in the paddock with McLaren publicly venting their frustration with an agreement being broken.
"We very unhappy with the FIA for losing yet another key employee to a racing team," Eric Boullier told Motorsport.com.
"Especially after it was agreed by all teams at the last Strategy Group meeting that no key technical FIA employees would be employed by a race team within 12 months of leaving the FIA.
"Ferrari went against the gentleman's agreement and the FIA has not enforced it."
Mekies will be joining Ferrari's technical team and will report to the Scuderia's technical director Mattia Binotto.