Paris - French consumer prices rose by 0.5 per cent in May, bringing year-on-year inflation to 3.5 per cent, the highest level since 1991, the government's statistical office INSEE said Wednesday.

The rise in consumer prices was primarily driven by the soaring cost of energy, which rose by 4.2 per cent over one month and 15.4 per cent year-on-year.

In addition, food prices increased by 1 per cent in May, and were up 5.7 per cent over the past 12 months, INSEE said.

The high inflation rate puts additional pressure on President Nicolas Sarkozy, whose popularity ratings remain low, in part because he is perceived to be incapable of raising the purchasing power of the French. (dpa)