William Boston:

PARIS—Hydrogen or batteries? When it comes to powering cars of the future, those are fighting words.
 
 Dieter Zetsche, chief executive of Daimler AG, and Carlos Ghosn, his counterpart at Renault SA and Nissan Motor Co., on Friday attacked Toyota Motor Corp.’s plans to launch a fuel cell powered vehicle, exposing a sharp divide over how they hope to comply with government policies to slash greenhouse gas emissions.
 
 Auto makers are growing concerned that weak consumer demand for electric vehicles threatens the billions of dollars they have invested in plug-in technology to meet ever stricter emissions regulations. Mr. Zetsche and Mr. Ghosn appear concerned that Toyota’s launch of a new “clean car” technology threatens to complicate the contest for consumer purchases and government subsidies.