FRANKFURT (Reuters) - German banks have around 23.5 billion euros (18 billion pounds) in credit exposure to Greece, but the systemic risk is limited as the biggest commercial banks, Deutsche Bank (>> Deutsche Bank AG) and Commerzbank (>> Commerzbank AG), hold only a tiny fraction of that, according to figures gathered by Reuters.

The lion's share of German exposure is held by the state-owned development bank KfW, with lending totalling 15 billion euros to the Greek state, the banking industry group BdB said.

Commerzbank said it held around 400 million euros in exposure to Greece at the end of September, while Deutsche Bank said it held around 298 million euros in exposure to corporate, bank and public debt.

Greek politics has weighed on markets including the euro as speculation intensified that Greece could leave the euro zone after a snap election on Jan. 25.

A study by JP Morgan found that the French bank Credit Agricole (>> CREDIT AGRICOLE) was the most exposed of Europe's commercial banks. Credit Agricole said it had 3.5 billion euros in exposure to Greek debt at the end of 2013.

France's largest bank, BNP Paribas (>> BNP PARIBAS), held around 0.7 billion euros in Greek debt at the end of 2013, according to data provided by BNP. Most of the exposure was to corporate borrowers and none was to Greek state entities, the bank said.

Societe Generale (>> SOCIETE GENERALE) held 0.3 billion euros in exposure to Greek corporate debt and had no sovereign exposure as of end-September, a spokeswoman for the bank said.

Of the total German exposure, 4.6 billion euros was to other banks, 3.6 billion to companies and private individuals, and 15.2 billion to state entities, the BdB said.

"The credit exposure of German banks in Greece is low," BdB head Thomas Kemmer said in a statement. "That's why, should it come to insolvency for Greece, the direct effects on German banks could be overcome.

"Even the contagion effects that would accompany an exit could be endured better than two or three years ago."

(Reporting by Kathrin Jones and Thomas Atkins; Editing by Kevin Liffey)