France's inflation rate declined for a third month in May, helped by lower energy prices as economic growth slowed.

Consumer prices rose 2.3 per cent from a year earlier based on EU methodology, compared with a 2.4 per cent increase in April, the Paris-based national statistics office, Insee, said today.

Economists forecast a 2.3 per cent gain, the median of 15 estimates in a Bloomberg survey showed.

A 26 per cent drop in London crude oil prices this year is combining with slowing growth to ease price pressure on households.

Energy prices fell 1.5 per cent in May from April, with oil products dropping 2.5 per cent.

"The price of energy and transport services and communications is falling," Insee said. "Food prices are up”.

Bloomberg