The Argentinean edged out reigning WTCC champion Yvan Muller by 0.018 seconds in the series' new staggered, single-lap, Q3 shoot-out qualifying format.
Muller lost time towards the end of his lap by slightly cutting the penultimate chicane and being forced to slow on the exit.
Sebastien Loeb looked set to beat Lopez's effort when he was 0.084s up in sector one and 0.018s up on the sector two spilt. But he had to settle for third behind his team-mates to complete a dominant showing for the Citroen C-Elysee.
"I knew that Yvan had made a small mistake, or a big mistake as I didn't see his lap, so there was no need to chance everything in the first sector," said Lopez.
"After that, I decided to push. I thought pole would depend on how much I wanted to take risks, but earlier [in practice] I wasn't trying that hard and I broke the suspension."
Muller was not too disappointed to miss out on pole, despite starting the session as favourite owing to his knowledge of the Moulay El Hassan circuit.
"Last year I started fourth or fifth and I still won the championship, so this isn't a big drama," said Muller.
ROAL Motorsport's Tom Chilton was the fifth and final driver in Q2 to make the cut for the decisive superpole session. The Briton's Q3 time of 1m44.864s secured fourth place and honours as top non-Citroen runner.
Chilton's progress came at the expense of fellow Chevrolet Cruze TC1 driver Dusan Borkovic, who was unable to complete his Q3 lap.
Rene Munnich will start race one from sixth, ahead of a trio of Hondas. Tiago Monteiro, who was the only representative of the works Honda team in qualifying, led Zengo Motorsport's Norbert Michelisz and Moroccan hero Mehdi Bennani.
Tom Coronel will start race two from pole position having set the 10th-fastest time in Q2, with Bennani, Michelisz and Monteiro lining up behind him.
Monteiro's team-mate Gabriele Tarquini sat out qualifying and will miss the race after sustaining accident damage in a collision with Gianni Morbidelli in the final free practice session. Superstars champion Morbidelli was also forced to sit out qualifying as a result.
The Q1 session, which determined the fastest 12 drivers to progress into Q2, was brought to a premature end when Campos SEAT Leon TC2 driver John Filippi crashed heavily on the exit of one of the chicanes.
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