"The (European) Commission has the perfect right... to negotiate as long as it wants" on the Transatlantic Trade and Investment Partnership (TTIP), Matthias Fekl told the French parliament's European affairs committee.
But he said he would reiterate the "clear" French position in favour of ending the talks at a meeting of EU trade ministers in Bratislava on 23 September.
The European Commission's mandate to negotiate the controversial treaty "no longer has France's political backing".
Fekl said the US side had failed to offer "any serious opening on any of the items that we wanted to put on the agenda," such as opening the public procurement market and protecting geographical labelling for products.
He had already signalled in August that Paris wanted to halt the talks, saying US negotiators were offering "nothing or just crumbs".
At the time European Commission President Jean-Claude Juncker said the negotiations - which began in mid-2013 - would continue.
The TTIP has become a hot potato as key elections approach in the United States, France and Germany.
Leaks about the proposed deal have sparked serious concerns among many Europeans that they will be giving up control over sensitive issues, such as the use of pesticides and hormones in food production.
Another issue that has raised concern is plans for a special court to speed up cases by companies against governments over breaches of regulatory issues, which opponents see as giving firms a veto over public policy, particularly in social and environmental areas.