PARIS (Reuters) -BNP Paribas reported a fall in first-quarter profit and revenue on Thursday but beat analyst forecasts, as lower expenses and a strong performance in its corporate banking business offset flat or falling revenues elsewhere.

The euro zone's biggest bank said group net income over the first three months of the year declined by 2.2% from a year earlier to 3.10 billion euros ($3.31 billion), beating the 2.4 billion-euro average of 19 analyst estimates compiled by the company.

Revenues over the period came in at 12.5 billion euros, down 0.4% but also above the average analyst estimate of 12.2 billion euros. The cost of risk - money set aside for underperforming loans - stood at 640 million, below the 819 million euros expected by analysts.

The French lender, which disappointed investors in February by delaying a key profitability target, struck an upbeat tone for 2024, reiterating its goal to generate full-year earnings of more than 11.2 billion euros.

It also gave a new target for group revenues, saying it expected them to exceed its 2023 distributable sales of 46.9 billion euros by more than 2%, and that the effects of cost cutting flagged previously would begin from the second quarter.

However, revenue was flat or falling in most of the bank's businesses.

Commercial and Personal Banking revenues rose 1% to 4.2 billion euros - above analyst estimates - but the net interest margins in the French business dropped sharply, BNPP said.

The net interest income, the difference between what lenders earn on loans and pay out for deposits, fell by 8% in France in the first quarter, as the cost of inflation hedging instruments offset a raise net interest income, the bank said.

The French retail market, which is typically less profitable than in other European countries because of stringent rules on mortgage and savings accounts, has proven difficult for BNPP.

The bank announced the abrupt departure last month of the head of the activity, Marguerite Berard, who was seen by some industry sources as a potential successor to CEO and company veteran Jean-Laurent Bonnafe.

Investors are watching banks' net interest income closely to see if the boost from rising interest rates, which has helped bank profitability - and their share prices - soar, is starting to fade.

BNPP's corporate and investment banking business revenue fell 4%.

Its global banking revenue rose 6.1% thanks to a jump in capital markets activities such as helping companies issue bonds.

But a downturn in BNPP's fixed income, currencies and commodities (FICC) trading business, which saw revenues slide 20% in the first quarter, was far worse than at the big Wall Street firms, where trading revenues declined on average by about 3% as market volatility weakened, according to Jefferies. ($1 = 0.9359 euros)