Shares in French banking stocks plunged Wednesday on renewed market jitters over their exposure to Greek debt and as market concerns about France's triple-A credit rating increased.

At 13.53 GMT Societe Generale was trading down 17% at €21.61; BNP Paribas was down 10.6% to €35.18; and Credit Agricole was down 9.7%% to €6.22; dragging down the CAC-40 index, which traded 2.9% lower.