UPDATE 1-Lagarde to extend French bank loan guarantees-paper

* Lagarde wrote to banks to demand action plan-Les Echos

* Lagarde hopeful French economic growth positive in Q3 (Adds Lagarde comments)

PARIS, Sept 13 (Reuters) - French Economy Minister Christine Lagarde plans to extend billions of euros of loan guarantees to France's top banks for another year and is calling on them to provide action plans on financing the economy, a newspaper said.

Lagarde has written a letter to the bosses of France's six biggest banks benefiting from state support to keep up pressure on them and encourage them to provide credit, daily Les Echos reported in a preview of its Monday edition.

In particular, the minister wants to know how the banks plan to revive lending to households and small and medium-sized businesses to reach a target of increasing volume by 3-4 percent, the paper said.

France's six big banks are Societe Generale (SOGN.PA), BNP Paribas (BNPP.PA), Credit Agricole (CAGR.PA), Credit Mutuel, Banques Populaire and Caisse d'Epargne (CNAT.PA). The latter two recently merged to create BPCE.

The government set up a rescue package worth 360 billion euros in taxpayer money last October, including a 40 billion euro recapitalisation fund. It is due to run until next month.

Lagarde said on television news magazine "7 a Voir" on channel France 3 on Sunday that the French were starting to "lift our heads above the water" following the impact of the financial and economic crisis.

The minister hoped France would post economic growth again in the third quarter, but added that a reversal in unemployment would be the real sign the crisis was ending.

"France, Germany and Japan were the only countries in the OECD (Organisation for Economic Cooperation and Development) which had positive growth in the second quarter of 2009. I am hopeful that the third quarter will be positive again," Lagarde said.

It would take several quarters for unemployment to start coming down following the stabilisation of the economy, she added.

"The true exit from the crisis ... will be when unemployment starts to reverse again," Lagarde said.

The Bank of France said on Sept. 8 that French GDP was expected to grow by 0.3 percent in the third quarter. (Reporting by James Regan; Editing Bernard Orr)