Dirar leaves Monaco after a five-year spell which started when he helped Monaco win Ligue 2 and promotion to Ligue 1 back in 2013.
The 31-year-old was also part of the squad that won Ligue 1 this season, making 18 league appearances with ten of them coming off the bench.
Fenerbahce previously confirmed via a club statement that they have reached an agreement in principal with Monaco for the transfer of the Casablanca-born midfielder.
But @FootballMorocco tweeted that the player has since signed a three-year-deal.
This was also confirmed by the player who was quoted saying:
"I am proud to have the chance to play in a big club like Fenerbahce. The stadium and facilities are very nice. I am very lucky to play in front of the big and enthusiastic Fenerbahce fans," he told fenerbahce.org.
"The matches I played against Fenerbahce with Monaco created serious memories on me," he added.
"The game we played here was an effect on my mix. We were very impressed with the stadium, fans, and atmosphere in that match. Since that day, there was Fenerbahce on one side of my mind ".
The North African started his career with Diegem Sport in Belgium, before spells with fellow Belgian outfits Westerlo and Club Brugge between 2006 and 2012.