“There is no evidence of consumer confusion,” Greenpeace, Humane Society International and other groups wrote in a letter dated April 1. “On the contrary, consumers purchase these items because they do not contain meat or dairy.”

The proposal must still pass the full European Parliament, which will not take it up until after elections in May. It would then have to be negotiated and agreed on by the Council of Ministers before becoming law, according to Neil Corlett, a European Parliament spokesman.

Whether the proposal is a maneuver by the meat lobby or simply an attempt by the French to assert food traditions, the proposal reflected a certain defensiveness by the meat industry as more and more people reduce their meat consumption, Ms. Scott Cato said.

“There was no consumer demand for this,” she said, adding that she would continue to oppose the amendment as “an attempt by the meat industry to make life harder for people” who prefer vegetarian diets.

In the United States, there has been a push by the dairy industry to require the Food and Drug Administration to enforce labeling rules for milk as more Americans switch to “alternative milks,” which come from any number of plants. (Pea milk, anyone?)

“Nobody thinks their almond milk comes from a cow,” said Michele Simon, the executive director of the Plant Based Foods Association in San Francisco.

As for efforts in some states to come up with labeling for plant-based meat substitutes, there was no confusion there either, she said. “People are happily buying these products not thinking they are beef,” she said.