"The feeling you get in rally is one of the most thrilling feelings I've ever experienced, and I was excited about driving one of these new WRCs in a race. It's nice to be able to do it in the team with which I've enjoyed so much success," he said.
Loeb took 78 wins before retiring from a full-time WRC career in 2012. He has started sporadic events since, the most recent being Rallye Monte-Carlo in 2015, before focusing on rallycross and cross-country rallies with Peugeot.
He has won the Spanish encounter eight times, with six wins in Mexico and four in Corsica.
"Everyone was pleased after the test sessions done this year, myself first and foremost, and these three appearances were the logical next step.
"I don't have any expectations, I just want to enjoy myself. I thought it made sense to take part in the French round, especially since I've always loved racing on Tarmac, although I'm not familiar with the current route of the Tour de Corse.
"Spain seemed like a good option too. And although I'm expecting it to be pretty tough given the time that has passed since I last competed there, I also wanted to contest a gravel rally.
"We opted for Mexico, since I have good memories of racing there and the route hasn't changed too much since I was last involved in the championship," said Loeb.
Citroën Racing director Yves Matton said Loeb's tests convinced him the 43-year-old had not lost his touch.
"I'm delighted to see there will be another chapter in the great history between between Sébastien Loeb and Citroën. He couldn't return to the WRC with anyone other than us!
"Seb confirmed he has lost none of his speed and skill during the test sessions, although he is bound to be short of knowledge of the stages and time in the car compared with the increasingly tough competition," said Matton.
