The Socialist president told business leaders last week that reform must reduce the tax load on companies and improve conditions for investment. The overhaul fits with Hollande's new embrace of a supply-side economics and move away from tax and spending increases.

Ministers, deputies, unions and employer groups will try to deliver by June proposals to simplify the system, which critics say is clogged with hundreds of small or ineffective taxes. No deadline has been set for turning the proposals into law.

Geoffroy Roux de Bezieux, the Medef business lobby's vice president, said companies would push for taxes to come down next year but expected little concrete change to emerge from the talks. "The real question is: what ground can we cover?" he said. "We're very much in a wait-and-see mode, and our hope is to see taxes come down as early as 2015."

(Reporting By Emmanuel Jarry; Writing by Nicholas Vinocur; Editing by Larry King)