BNP Paribas, France’s largest bank, fell as low as 23.05 euros, the lowest since March 9, 2009. The stock was down 1.77 euros, or 6.8 percent, to 24.35 euros by 11:57 a.m. Societe Generale (GLE) SA fell 2.5 percent to 15.19 euros, while Credit Agricole SA (ACA) slid 0.5 percent to 4.80 euros.