Industry ad hoc association EU Pro Sun in July filed a complaint stating solar power components imported from China into the European market were at prices below fair market value.
"In terms of import value affected, this is the most significant anti-dumping complaint the European Commission has received so far," the commission said in a statement.
The European Commission said it would take about 15 months to examine whether injury was caused to the European solar market by the alleged dumping of goods.
China exported around $26 billion worth of solar power components to the eurozone last year. Chinese-manufactured solar products account for 65 percent of the global market and dominate Europe in terms of exports.
Dennis Pamlin, founder of the pro-Beijing 21st Century Frontiers group in Sweden, told state-controlled newspaper China Daily the move by Europe amounted to a trade war. It's not a "smart move" given European ambitions for renewable energy, he said.