A defiantly upbeat François Hollande has announced that economic recovery is under way in France – despite a mood of economic gloom, recession, spending cuts and record unemployment.

The French president, who has been battling low approval ratings and dissent within his party as well as government ranks, used a TV interview for Bastille Day celebrations on 14 July to push a new optimistic official line, vowing to "fight" French pessimism.

"The economic recovery is here," he said, adding that it was "very slight" but insisting that industrial production had picked up, there had been a small recovery in consumption and job hires had started to increase. But commentators were quick to question the rise in industrial production this spring which had appeared to drop again shortly after.

Hollande vowed to tackle France's standing as the most pessimistic country in Europe, "perhaps in the world", lamenting: "There are countries at war who are more optimistic than us."

He acknowledged that France was still struggling to get its deficit under control and that he could not rule out more tax rises to help balance the budget. But he said: "I will increase taxes only if necessary, ideally as little as possible."

Hollande also used the interview from the sun-drenched gardens of the Elysée Palace to contain a growing row over shale gas in France. "As long as I am president, there will be no exploration for shale gas in France," he declared, putting an end to speculation that France might lift its ban on controversial drilling techniques.

Ever since Hollande sacked his environment minister Delphine Batho this month after she criticised government budget cuts, the president has been under pressure to prove that he is serious about ecology and is not in thrall to the oil and gas lobby. Batho had said that her opposition to shale gas drilling cost her her job, and that lobbies in favour of shale gas and nuclear power had wanted her "scalp".

The International Energy Agency has named France as a European country with some of the most plentiful underground reserves of shale gas. But France is one of the few countries that has outlawed the controversial and potentially polluting process of hydraulic fracturing – or fracking – in drilling for shale gas. The ban, which was voted in under Nicolas Sarkozy, has been continued by the Socialist Hollande, who has two Green ministers in his government.

But a legal challenge to the fracking ban has been brought by a US firm which remains keen to explore in the southern French countryside. Debate was further stirred recently when the outspoken industry minister, Arnaud Montebourg, suggested creating a state-backed company to examine exploration techniques.

Hollande also insisted on the importance of maintenance of French train lines after a passenger train derailment south of Paris caused six deaths.