While the proven Zacks Rank places an emphasis on earnings estimates and estimate revisions to find strong stocks, we also know that investors tend to develop their own individual strategies. With this in mind, we are always looking at value, growth, and momentum trends to discover great companies.Of these, value investing is easily one of the most popular ways to find great stocks in any market environment. Value investors use tried-and-true metrics and fundamental analysis to find companies that they believe are undervalued at their current share price levels.In addition to the Zacks Rank, investors looking for stocks with specific traits can utilize our Style Scores system. Of course, value investors will be most interested in the system's "Value" category. Stocks with "A" grades for Value and high Zacks Ranks are among the best value stocks available at any given moment.Carrefour SA (CRRFY) is a stock many investors are watching right now. CRRFY is currently holding a Zacks Rank of #2 (Buy) and a Value grade of A. The stock holds a P/E ratio of 10.82, while its industry has an average P/E of 23.38. Over the past year, CRRFY's Forward P/E has been as high as 13.36 and as low as 9.41, with a median of 10.69.CRRFY is also sporting a PEG ratio of 1.36. This metric is used similarly to the famous P/E ratio, but the PEG ratio also takes into account the stock's expected earnings growth rate. CRRFY's industry has an average PEG of 3.65 right now. Over the past 52 weeks, CRRFY's PEG has been as high as 1.51 and as low as 0.80, with a median of 1.13.Another valuation metric that we should highlight is CRRFY's P/B ratio of 1.21. The P/B ratio pits a stock's market value against its book value, which is defined as total assets minus total liabilities. This stock's P/B looks attractive against its industry's average P/B of 3.61. CRRFY's P/B has been as high as 1.44 and as low as 0.80, with a median of 1.09, over the past year.Value investors will likely look at more than just these metrics, but the above data helps show that Carrefour SA is likely undervalued currently. And when considering the strength of its earnings outlook, CRRFY sticks out at as one of the market's strongest value stocks.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Carrefour SA (CRRFY): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research