Carrefour's shares were up 3.6 percent in early trading, helping to lift the stock price of its French rival Casino by around 1 percent.

"While we expect the sales trend to slow in coming quarters, we see the new initiatives launched in Q1, including additional price investments and new formats as steps in the right direction," wrote Deutsche Bank analysts.

"But we lack sufficient visibility about the scale of investments and targeted positioning compared to peers, and notably Leclerc, to gain confidence in the potential success of the turnaround plan," added Deutsche Bank, as it kept a "hold" rating on Carrefour shares.

(Reporting by Sudip Kar-Gupta; Editing by Mark Potter)