China on Thursday fined several foreign eyewear makers more than 19 million yuan ($3.1 million) for "price manipulation", the government said, in the latest targeting of overseas firms in the giant market.
The powerful National Development and Reform Commission (NDRC), China's top economic planner, launched an investigation last August into alleged violations of anti-monopoly law in the sector, the agency said in a statement.
Five companies -- all foreign -- were given penalties ranging from 1.7 million yuan to 8.8 million yuan, it said.
They included units of France's Essilor, Germany's Carl Zeiss and Japan's Nikon, as well as Bausch & Lomb and Johnson & Johnson -- both of the United States -- according to the statement.
"All operators should take heed, be more law-abiding, consciously regulate their own prices and maintain market order for fair competition," it said, adding some companies had used coercive methods to maintain prices.
Japan's Hoya and another company whose name was given as Shanghai Weicon also faced investigation but escaped fines for providing evidence and acting to "rectify" the situation, the NDRC said.
It is unknown whether Shanghai Weicon has any relationship with German adhesive maker Weicon.
Last year, China launched similar probes into foreign firms' pricing for goods ranging from drugs to baby formula, moves which were perceived as ways to exert pressure on companies to control retail prices.
China eventually fined six mostly foreign baby formula producers, including New Zealand's Fonterra, for price-fixing as it sought to cool public anger over high costs in the sector.
Earlier this month, Chinese authorities accused a top GlaxoSmithKline executive of ordering employees to commit bribery, following a 10-month probe into the British drugmaker.