The move came after the German head of the main conservative grouping in the European Parliament insisted there is growing "anger" over Prime Minister Theresa May's insistence that Britain plays a full role in the EU until it leaves - and that this could impact on the Brexit "divorce" deal.
May called on European Union leaders to work together for a "smooth" withdrawal following Britain's shock June vote to leave the bloc, but Hollande said her apparent preference for a decisive break means she will not get an easy ride.
European Union leaders came together in Brussels in Thursday for a two-day summit. MECHANICS OF NEGOTIATION May has said she will launch the formal, two-year process of negotiating Britain's exit from the EU before the end of March 2017 and London wants to use the interim period to sound out European counterparts and decide its priorities for the talks.
But Tusk warned that once Article 50 is triggered, "we have our right and also our legal obligation to meet as 27 to discuss our strategy".
There will be "difficult" moments in the Brexit negotiations which will require "some give and take", the Prime Minister has said.
In the early hours of Friday, after a lengthy discussions with the other European Union leaders over dinner about Russia's military action in Syria and Europe's migration crisis, she spoke briefly and in broad terms about the U.K.'s government's preparations for negotiations.
Mrs May said she had played an active role in discussions and was not "backwards in coming forwards".
But her stated intention to prioritize cutting immigration, if necessary at the expense of access to the single market, has alarmed investors and sent the pound plunging.
"If it is reversible or not, this is in the British hands".
"They agreed we should approach the Brexit negotiations in a positive and constructive spirit to ensure the process is as smooth and orderly as possible".
Once May activates the exit clause - Article 50 in the EU's governing Lisbon Treaty - negotiations on the terms of Britain's departure would run for two years. "But this choice will have consequences", he said, adding that Brexit is an "alarm bell that must wake up the sleepwalker who is heading toward the cliff".
But EU leaders are unlikely to turn a blind eye to any restrictions on free movement of workers from the bloc. "The danger that I can see is that we end up doing something this is mutually self-harming".
"We are not looking to adopt another model that somebody else has in relation to their trade with the European Union".
European leaders buried May's address in the summit agenda, first addressing concerns about Syria, Russia and concerns about refugees fleeing the Middle East.
"I said very firmly: Theresa May wants a hard Brexit?"
He said Hungary felt close to the United Kingdom and wanted close relations after Brexit, but he warned that "not everybody belongs to this club".
Referring to the government's refusal to offer a "running commentary" on talks, committee chairman Lord Boswell said: "What they offer instead, namely parliamentary scrutiny after the fact, is in reality not scrutiny at all - it could be no more than a rubber stamp".