European capitals have welcomed agreement on what most hailed as a good post-Brexit trade deal between the UK and the EU – but described it as the least-worst outcome and warned they had yet to study the fine print.

Emmanuel Macron said European “unity and firmness have paid off” but Paris would now be checking to make sure the deal protected the French fishing industry.

The 2,000-page treaty was “essential to protect our citizens, our fishermen, our producers … We will make sure this is the case,” the French president tweeted, adding that Europe could now look to the future “united, sovereign and strong”.

Germany’s Angela Merkel was pleased with an agreement “of historic significance”. Berlin would now study the text “intensely”, the chancellor said, and expected “soon to be in a position where we can judge whether Germany can support today’s result … I am optimistic that we have a good result in front of us here.”

Merkel said the German cabinet would meet by telephone on 28 December to decide its stance, but added that the agreement “cannot finally enter into force until the European parliament has also given its approval”.

Micheál Martin, Ireland’s taoiseach, said Dublin would also now “consider the detail of the text very carefully”. The Brexit journey had been “long and difficult”, he said, and implementation of the Northern Ireland protocol would be critical.

Ireland’s fishing communities “will be disappointed with the outcome”, Martin admitted, but “compared with no deal, which would have seen them completely excluded from British waters, negotiators have worked hard to minimise the damage”.

Irish businesses would, however, now be facing “new customs and regulatory formalities, procedures and checks”. There was “no such thing as a ‘good Brexit’ for Ireland”, Martin said. The agreement was “the least bad version of Brexit possible”.

Ireland’s European affairs minister, Thomas Byrne, said it was “a bittersweet day for us. We hated to see Britain leaving, but we couldn’t wait to conclude the deal to do so.” Austria’s chancellor, Sebastian Kurz, said Vienna would study the text.

MEPs said the UK’s compliance with the agreement would be closely watched. The chair of the parliament’s environment, public health and food safety committee, Pascal Canfin, tweeted that he would be “extremely careful”.

Canfin said his committee would “ensure full implementation of the provisions protecting EU citizens and companies manufacturing in the EU from climate dumping and non-compliance with our food safety standards” by UK companies.

Philippe Lamberts, the head of the Greens in the European parliament, said the bloc’s primary goal had “always been to protect the integrity of our single market, one of the key foundations of the union, and it seems this deal achieves that”.

Lamberts said, nonetheless, that “the devil is always in the detail” and the parliament would insist on being given “the proper time to scrutinise and potentially ratify such a wide-ranging deal. We are not just here to rubber-stamp agreements.”

Spain’s prime minister, Pedro Sánchez, said in a tweet that he welcomed the deal but warned that talks between Spain and the UK over how Brexit would affect the British overseas territory of Gibraltar had not yet been concluded.

Sánchez said member states would examine the deal and the EU council would make clear its position in the coming days. “Dialogue continues between Spain and the UK to reach an agreement on Gibraltar,” he added.

Fabian Picardo, Gibraltar’s chief minister, said the deal did not cover Gibraltar and that “for us, and the people of the Campo de Gibraltar around us, the clock is still ticking”.

His administration would “continue to work, hand in glove with the UK, to finalise negotiation with Spain of an agreement for a proposed treaty between the EU and the UK in relation to Gibraltar”, Picardo said.

Mark Rutte, the prime minister of the Netherlands, one of the toughest of the EU27 in several aspects of the negotiations, hailed the deal as “excellent news”, but the Dutch foreign minister, Stef Blok, said The Hague would be examining the text with great care.

“We will pay particular attention to the agreements on a level playing field, the access of Dutch fishing boats to British waters, and the governance of the agreement,” Blok said, adding: “There is very little time to do this.”

The Belgian prime minister, Alexander De Croo, said only one thing mattered to him: “Ensuring the best possible protection for Belgium’s economic interests. We must protect our Belgian companies from unfair British competition.”

The agreement offers the prospect of “maintaining our strong relationship with the UK after Brexit, but provides crucial guarantees for fair competition for our companies”, he said.

Portugal’s prime minister, António Costa, said his country “warmly welcomed” the agreement, adding that UK would remain “in addition to our neighbour and our ally, an important partner” after 1 January.

Franziska Brantner, Europe spokesperson for the German Greens’ parliamentary group, said the EU27 had “not allowed themselves to be divided by Johnson’s brinkmanship” and would now “check whether conditions for fair competition and the option of sanctions against dumping are solidly anchored in the text”.

European commentators were not charitable. “The trade deal doesn’t match the promises made after the EU membership referendum in 2016,” said the weekly Die Zeit. “Back then, the promise by Johnson was that the UK would keep the advantages of EU membership.

“That is no longer the case. In spite of an agreement, cross-country trade will have to bear the weight of more bureaucracy and more border controls. The deal does not apply to services, especially not financial services. Free movement of workers is no longer provided.”

The Spanish daily El País said London had “seen in recent hours, as a result of border closures, the monumental damage that a no-deal Brexit would have caused. The British side would be the hardest hit by a chaotic exit from the single market – a risk that has been on the table in recent weeks and now is avoided.”