It said the 2015 prediction was "not out of reach," but added "the macroeconomic scenario presented by the government contains several weaknesses and is subject to various risks," relying on a rebound in consumer confidence and revenues from recently announced supply-side measures.
It called the 2016 and 2017 forecasts "optimistic" - a euphemism for unrealistic.
The 2014 and 2015 forecasts are well above those of a Reuters poll of economists last week, which put growth at 0.8 percent this year and 1.2 percent next year, with France missing the deficit reduction target.
Economic data released on Wednesday did little to support government optimism. The private sector expanded at a much slower rate in April, surveys showed, underlining the fragility of the recovery.
French governments of left and right have a track record of basing budget plans on rosy growth and revenue assumptions that lead to a higher deficit when growth falls short.
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A new EU budget review procedure gives the Commission more power to challenge figures its own economists deem unrealistic and send a national budget plan back for redrafting.
Diplomats said in advance of the plan that if it aimed for a 3 percent deficit next year, a lame-duck Commission in its last months in office would probably not want to clash with Paris.
In 2013, France missed its target of 4.1 percent and its deficit ended the year at 4.3 percent of GDP.
Some officials in Paris hoped that Italy's new socialist prime minister, Matteo Renzi, would be an ally in bending the EU targets. But Renzi, whose country is already under the 3 percent deficit limit, has decided to play by the rules.
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