WASHINGTON — The French economist Jean Tirole, a student of imperfect markets, has spent decades dissecting the many industries where competition does not fulfill the textbook promise that prices will be low and quality will be high.

Mr. Tirole’s work has helped governments to improve cable television service, to restrict credit card fees and to crack down on harmful monopolies.

And on Monday, it won him the Nobel Memorial Prize in Economic Science.

Mr. Tirole’s work has clarified “what sort of regulations do we want to put in place so large and mighty firms will act in society’s interest,” Tore Ellingsen, the chairman of the selection committee, said after the announcement ceremony.

The choice of Mr. Tirole, a professor at the Toulouse School of Economics, comes after the 2008 financial crisis revealed shortcomings in the regulation of banks and other financial firms, and with increasing scrutiny, particularly in Europe, about the market power of technology companies like Google and Apple.