France to try progressive energy prices to cut power demand-MP

* MP says new energy bills as soon as autumn 2013

* Law will not concern long-term regulated tariffs

* Three-tier system cost neutral for utilities, govt

PARIS, Sept 5 (Reuters) - France will seek to curb power consumption by making energy bills progressive, linking power bills to consumption, household size and location, the lawmaker sponsoring the bill presented on Wednesday said in a interview.

The progressive power tariffs -- a major pledge in President Francois Hollande's campaign manifesto -- are expected to be cost-neutral for the government and utilities such as electricity giant EDF and could be implemented as soon the autumn of 2013, the Socialist member of parliament said.

"Our objective is to save energy. It's good for the planet, good for our trade balance, and good for energy bills," MP Francois Brottes told Reuters ahead of the presentation of the bill in parliament, where it is expected to be debated until mid-November.

"It's a model change. The goal is to set an objective for a fall in power consumption, without a loss of confort," Brottes said, declining to put a figure on that decrease target.

High energy prices are a hot topic in France, where a stagnant economy is hitting consumers' purchasing power and prompting the new Socialist government to cap the rise in regulated power prices to 2 percent this summer, angering gas group GDF-Suez and EDF.

However, the proposed law will not touch the issue of the evolution of regulated electricity and gas tariffs, Brottes said.

Brottes, Hollande's former campaign energy adviser, wants households to be charged according to a three-tier tariff system, with each family being given an allowance for a certain amount of kilowatt-hour at a lower price than the current single one.

Over that base amount, which he said would be derived from the household's size, geographical location and the home's insulation efficency, tariffs would increase in two stages, coaxing consumers to cap their consumption.

Brottes said the actual threshold had yet to be decided and will be debated in parliament.

The law will also include an amendment banning energy providers from cutting power supply in case of unpaid bills in the winter, he added. (Reporting by Benjamin Mallet and Michel Rose; Editing by Leslie Gevirtz)