(Reuters) - France's largest carrier Orange topped an annual quality review of mobile services carried out by the country's telecoms regulator, while Iliad's Free Mobile lagged competitors.

ARCEP, the telecoms regulator, carried out 90,000 measurements of voice, texts, and web surfing on the four French mobile operators in the first quarter of this year. New fourth generation networks now being built by operators were included for the first time.

The survey evaluated 258 different indicators - from traffic capacity and the speed of file transfers to the quality of watching movies and internet browsing - indicating significant differences between operators.

"Orange gets the best results for the telephony service and for most data services," ARCEP said in its report.

Iliad's Free Mobile service, which launched its mobile service in January 2012 and is still building its 3G network, "got significantly worse results on a large number of indicators".

While Iliad works to build its network, it has a contract with Orange to carry its traffic, allowing Free Mobile to provide services to consumers even where it has no mobile antennas.

Orange showed above-average performance on 213 indicators, against 75 for Bouygues Telecom, 38 for SFR, the Vivendi subsidiary, about to be acquired by Numericable. Free Mobile outperformed on only two measures.

SFR's results are below some previous years in which it has come out ahead of Bouygues and close to Orange. A spokesman for SFR said the lower service quality was caused by the technology choice the operator had made on how to upgrade its network to 4G, which required it to turn off antennas as it went.

"The renovation of our network has caused some problems and interruptions this year," said the spokesman. "We hope we will be back at the top of the ARCEP survey next year once our network modernisation is behind us."

Bouygues Telecom did not return a request for comment, while Iliad declined to comment.

Orange said it welcomed the results: "We have come in first in the past four years and are largely ahead of our competitors," said a spokeswoman. "It validates our strategy to differentiate ourselves by the quality of our networks."

(Reporting by Gwenaelle Barzic and Leila Abboud; Writing by Maya Nikolaeva, editing by David Evans)