UPDATE 1-French May new car sales rise 11.9 percent-CCFA

* Scrapping scheme, new registration system boost May sales

* Car sales down 1.4 percent in first four months

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PARIS, June 2 (Reuters) - French new car sales rose 11.9 percent in May, as scrapping incentive schemes and the shift to a new system of car licence plates boosted numbers, manufacturers' association CCFA said on Tuesday.

The French government introduced a scrapping scheme -- whereby drivers get cash bonuses for trading in old cars for newer, greener models -- earlier this year, to boost flagging sales as French manufacturers PSA Peugeot Citroen (PEUP.PA) and Renault (RENA.PA), like their competitors worldwide, were hit by a global auto sales slump.

A CCFA spokesman said separate special offers made by manufacturers may have helped May's new car tally, as carmakers battle to clear stocks of unsold vehicles.

And the introduction of a new system of vehicle registrations in mid-April may have pushed some registrations of cars bought last month back into the first few days of May, he added. France dropped departemental numbering systems with white and yellow plates for a national system with black lettering on two white plates.

PSA Peugeot Citroen recorded a 20.7 percent increase in new car sales for the group as a whole in May, a month with the same number of working days as May 2008.

Its Peugeot brand saw a 14.5 percent increase while Citroen -- with a range including new models such as the C3 Picasso -- saw sales rise 28.2 percent.

Renault group sales declined 1.7 percent, with a 4.1 percent dip for Renault brand sales and a 42.1 percent increase for its Dacia brand.

There were 206,387 registrations in May. Over the first five months of the year, car sales declined 1.4 percent.

(Reporting by Helen Massy-Beresford, editing by Marcel Michelson)