The new German government plans to legalize cannabis.

Besides climate politics, digitalization and a higher minimum wage, the coalition has agreed on one fringe issue Chancellor Angela Merkel’s party has blocked for years.

Germany’s new government wants to legalize marijuana.

“The legalization of cannabis, long blocked by the Union, allows us to have a regulated and taxed dispensary, controllable quality and effective youth protection through education,” wrote Lars F. Lindemann, a regional cadre of the Free Democrats, on Twitter.

The parties in the new coalition have agreed to legalize the sale of cannabis — as long as it is sold in licensed establishments that can tax it properly and ensure both quality control and that it is sold only to adults. After four years, the parties vow to re-evaluate the law and its effect on society.

If Germany does legalize recreational marijuana, it will become the first major European country to do so, after Canada and certain U.S. states, opening a significant market for legal cannabis growers and dealers. (Other European countries like the Netherlands have decriminalized the drug, but producing, buying and selling remains legal only in medical contexts.)

Under current German law it’s not illegal to consume cannabis but it is to buy it.

Criticism of the plan came swiftly. Markus Blume, the party secretary of the CSU, the Bavaria-only sister party to Ms. Merkel’s C.D.U., called the idea a “dangerous experiment” and warned that cannabis acted as a gateway drug.

“It makes a drug that is harmful to health into a lifestyle product,” Mr. Blume said of the proposal.

Indeed, Mr. Blume is not alone. A study released last month found that only 30 percent of respondents thought the drug should be legalized for recreational use. Another 59 percent believed it was better left the way it has been since 2011: a medicinal product that requires a doctor’s prescription.

And while the Greens campaigned on clear rules for cannabis use and the Free Democrats have argued legalization could bring money into state coffers, the outgoing conservative government insists legalization is dangerous.

“Cannabis legalization would be a breach of the dam,” Stephan Pilsinger, the conservative parliamentary faction expert on drugs, said in October. “At some point, unfortunately, we’ll be talking about legalizing all drugs.”