"Too much suffering, not enough hope, that's France today," Valls told the National Assembly, insisting that he had heard the message sent by the Socialists' defeats in this month's local council elections.
"I have no enemies on the left," he said, declaring that he would work with the Green party, EELV, despite the fact that its two ministers quit the government when President François Hollande appointed him last week.
He also proposed to meet the leaders of the right-wing opposition, the big winners in the municipal polls.
Valls went on to outline measures that he hopes will persuade employers to take on workers and tackle France's high unemployment, while reducing the budget deficit as promised to the European Commission.
Labour costs will be cut by 30 billion euros, he claimed.
Employers will pay no social security contributions for workers earning the minimum wage and less for those paid slightly more, he promised, and a number of taxes will be axed or cut.
"The government has kept its word, it's up to employers to keep to their commitments," he said.
Low-paid workers' social security contributions will also be cut, raising their take-home pay.
As part of Hollande's Responsibility Pact, 50 billion euros will be cut from the budget - 10 billion from local councils, 19 billion in central govenrment spending and 10 billion from the health budget - will be made.
Valls called for a loosening of the European Union's monetary policy to try to boost growth and a streamlining of state administration.
The new prime minister also rejected charges, repeated by Rwandan President Paul Kagame this weekend, that French troops were implicated in the genocide in his country in 1994.