PARIS (Reuters) - Germany should act sooner rather than later to revive its flagging economy, France’s finance minister said on Thursday, as he struggled to hide frustration with the pace of Berlin’s efforts to engineer a recovery.

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French policymakers are growing anxious as Germany, Europe’s largest economy, dithers over how to pull itself back from the brink of recession, and they want Berlin to do more with its budget surplus.

In a news conference alongside Germany’s finance and economy ministers, French Finance Minister Bruno Le Maire said the two countries had agreed on a strategy to respond to the global economic slowdown and trade tensions, which are hitting Germany’s export-driven economy particularly hard.

He said that the strategy was based on three pillars: “Keep reducing public debt where it is necessary. And it is the case in France; keep pursuing structural reforms, as we are doing in France; have budget policies that can take up the baton from monetary policy.”

However, Le Maire said that while there was agreement on the approach there remained an open debate on the timeframe for action.

“I recognize perfectly well - Olaf Scholz and I talk a lot about it - that Germany has started spending more money, but there is still a debate on the timeframe,” Le Maire said, referring to the German finance minister.

“Germany is ready, we continue to believe that it’s already right now necessary to activate this strategy,” he added.

Seeking to underline Franco-German economic cooperation, Le Maire said a pilot plant in France to manufacture electric car batteries will go online in 2022, two years before a second factory opens in Germany, part of a pan-European project to rival Asia’s dominance of the battery market.

France's Saft, a unit of oil and gas major Total TOTF.PA, will lead the first consortium, Le Maire said.

Addressing the subsidy row between European planemaker Airbus AIR.PA and rival Boeing BA.N, Le Maire said Paris and Berlin both hoped for an amicable solution while acknowledging the European Union may face U.S. sanctions.

“If the United States imposes sanctions, it must know that we are ready to respond, once again under the auspices of the World Trade Organization.”