Société Générale, France's second-largest listed bank, said it had booked a €525m writedown on the value of its Russian unit Rosbank after months of political crisis in Ukraine.
The goodwill charge marks a blow to SocGen's ambitions in Russia.
It has poured billions into restructuring Rosbank in the face of tough competition from local state-owned players and the arrest last year of its top Russian executive on bribery charges.
SocGen blamed heightened uncertainty as well as the decline in the Russian rouble for the writedown but said it expected to achieve "satisfactory" returns in Russia in 2016.
The crisis in neighbouring Ukraine has seen Western sanctions imposed on Russia and threatens to scare off investors.
The International Monetary Fund has said Russia is already "experiencing recession" while the Organisation for Economic Co-operation and Development cut its economic growth forecasts.
SocGen today reported a 13.3% drop in first-quarter net income to €315m despite a 14% increase in revenue.
Stripping out the writedown, SocGen's net income would have been €941m, or higher than the €911m average analyst forecast as compiled by Thomson Reuters I/B/E/S.
Larger domestic rival BNP Paribas also booked losses linked to the Ukraine crisis in the first quarter, though these were overshadowed by BNP's warning that it may be hit with a fine far in excess of the $1.1 billion it set aside to cover litigation costs linked to potential US sanctions breaches.
SocGen said its core Tier 1 capital ratio under Basel III rules had risen to 10.1% at the end of March from 10% at the end of December.
SocGen's corporate and investment bank, which is traditionally weighted more towards equities trading than fixed income, was not immune to the fixed-income slump that has hit rivals such as British bank Barclays.
SocGen said fixed-income revenue fell 25.3% in the first quarter, while equities revenue rose 9.3%.
Overall, its investment banking and asset management division saw earnings drop 15.2% to €481m.
French retail banking fared better thanks in part to a 28% drop in loan-loss provisions. SocGen's international retail bank, however, swung to a loss on the Russian charge.