PARIS- France needs to start working now on plans to rein in its debt once the economy has put the coronavirus crisis firmly behind it, which is not expected until 2023, the International Monetary Fund said on Tuesday.

In an annual in-depth review, the IMF forecast that the euro zone's second-biggest economy would rebound 5.5% this year after contracting 9% in 2020.

But it said the recovery would remain below the pre-crisis trend -- when French growth was outpacing other euro zone economies -- as corporate balance sheets strained by the crisis and high unemployment weighed on activity.

French Finance Minister Bruno Le Maire has forecast a rebound of 6% this year, although he has also warned that that will be challenging after a slow start to a national vaccination campaign.

With the crisis expected to leave the public sector budget deficit at 7.7% of gross domestic output this year, the IMF urged the government to lose no time drawing up plans to tackle spending once the economic recovery takes hold.

"Debt in France is high and we think that now is the time to develop and approve a credible medium-term fiscal consolidation plan," the IMF's France mission chief Jeffrey Franks told journalists on a conference call.

He said that the effort should only begin if growth is positive, economic output has returned to pre-crisis levels and risks have subsided.

The IMF thus does not envisage fiscal consolidation starting under its current forecasts until 2023, he said, which means the government could be spared a major belt-tightening effort until after a May 2022 presidential election.

(Reporting by Leigh Thomas; Editing by Catherine Evans) ((leigh.thomas@thomsonreuters.com; +33 1 4949 5143;))