But while billed as a free-trade pact, the limited information released about its terms suggests that the details of any final deal may focus on adjusting import-export quotas and fine-tuning regulations as much as the easing of tariffs.

Stephen Harper, the prime minister of Canada, has repeatedly emphasized the importance of a trade pact with Europe. Despite that, the negotiations, which began in 2009 and largely took place out of public view, provoked relatively little notice in Canada. Dairy farmers, who enjoy tight controls on imports, have been critical, as have some groups fearing the pact may increase the cost of drugs.

Most of the political controversy in Canada focused on Mr. Harper’s presenting a legislative agenda for a new session of Parliament on Wednesday and then leaving for Brussels the next day, before he could be questioned. An agreement on the trade deal had not been expected this week and opposition politicians charged that Mr. Harper had announced the pact on Friday to deflect attention from an expenses scandal involving some of his Conservative appointees.

“This is the biggest deal our country has ever made,” Mr. Harper said in Brussels on Friday, calling it a “historic win for Canada.”

Announcing the deal, Mr. Harper and José Manuel Barroso, the president of the European Union, said they hoped it would be in effect by 2015.

Once a final text of the agreement is completed and signed, it would require ratification by the European Parliament, all of the European Union’s 28 member states and every Canadian province and territory.

Any Canadian pact with Europe will pale in economic terms with the 1988 trade deal between Canada and the United States, which was folded into the North American Free Trade Agreement. According to the Canadian government, the United States accounted for 69.5 percent of its international trade in 2011, when Canada had exports of $532.4 billion, while Europe accounted for only 10.4 percent. The European Commission estimates that Canada accounts for about 1.8 percent of its external trade.

Once the agreement is put into effect, the European Commission expects trade between Canada and the European Union to increase nearly 23 percent, or 25.7 billion euros ($35 billion).

“Businesses in both Europe and Canada will be delighted to see new market opportunities open up at a time when global economic performance remains sluggish,” said Markus J. Beyrer, the director general of Business
Europe, an industry lobby group in Brussels. “We look forward to seeing the technical aspects of the agreement concluded quickly.”

While in Canada, the talks have not been prominent, the business community has generally been supportive.

As a result of the pact, Canada said that 98 percent of European tariffs on Canadian goods would be lifted, though neither Canada nor Europe offered a similar statistic for Canadian tariffs. Some tariffs are more significant than others. Several sectors of Canada’s agricultural industry — dairy, poultry, eggs and pork — are protected by tariffs as high as 300 percent, as well as by import quotas.

Groups representing dairy farmers and cheese makers in Canada said they had been told that while the tariffs would remain, Europe would be allowed to export about 33,000 tons of cheese a year to Canada duty-free, an increase from about 14,000 tons.

Europe has long wanted Canada to match its longer patent protection for pharmaceutical drugs. It appears that Canada has agreed to extend patents by two years for drugs that are subject to lengthy reviews. Canadian provinces, which deliver health care under Canada’s public system, have demanded compensation for any increased drug costs.

But, as with everything else about the agreement, the details regarding drug patents remained fuzzy. Stuart Trew, a trade researcher for the Council of Canadians, a nationalist group, said that secrecy surrounding the deal’s specifics made it difficult to assess its impact. “There’s been a wall of confidentiality that has stopped any serious discussion,” Mr. Trew said.

While the negotiations have had an even lower profile in Europe than Canada, the tentative deal received similar praise from businesses and some politicians there.

David Cameron, the British prime minister, said the deal would inject £1.3 billion, or about $2.1 billion, into Britain’s economy, increase exports to Canada by about a third, create thousands of jobs, and give a fillip to the negotiations for a deal between the Europe and the United States.

“We must now seize on today’s success,” Mr. Cameron said, “and focus our efforts on concluding all the other trade deals on the table.”

James Kanter contributed reporting from Brussels.