Police arrested five people after a group of anti-capitalist protesters set up a temporary camp outside the London Stock Exchange following May Day demonstrations.
Between 50 and 100 activists moved into Paternoster Square with tents and supplies from around 7pm last night - but were forced to leave by officers just hours later.
It comes more than six months after members of campaign group Occupy London were prevented from occupying the square in heart of the City of London.
Instead activists set up camp outside St Paul's Cathedral just yards away from the stock exchange and remained there for four and a half months.
However, last night's demonstration was much more short-lived despite Occupy saying that protesters had "fulfilled" a goal.
A spokesman for the campaign group said: "This was something we have wanted to do on October 15 and we have finally done it.
"This is a force that will not be stopped."
Activists, who were prevented from occupying the area by police last October, moved onto Paternoster Square yesterday evening despite an injunction being in place making it illegal to stage protests there.
One protester set up camp on the Paternoster Square Column unfurling a banner reading "Occupy London", while a row of six tents were set up at one end of the square.
Around 30 to 40 police officers were dispatched to the site and formed a semi-circle around the demonstration, telling protesters they had 30 minutes to leave the area. The tents were swiftly picked up and removed from their temporary pitches.
Those who remained within the square after the half hour police warning were told they faced arrest if they refused to leave the area immediately.
A spokesman for City of London Police said all the demonstrators had been dispersed by just after midnight and officers had arrested three men and two women on suspicions of breaching section 14 of the public order act. There was no violence during the occupation, the spokesman said.
Activist Tanya Paton, 40, from Halstead in Essex, said protesters were "delighted" to have briefly set up camp in Paternoster Square.
"As long as the Government continues to serve the super-rich, we are going to continue to fight and try and change things," she said.
Musician Denis Fernando, 36, from Wembley, north west London, promised further action, adding: "We are the first green shoots of what's going to be a very long spring."
Earlier, members of the Occupy group handed out thousands of flowers to passengers at London's Liverpool Street station, bearing the message: "There Is Something Better Out There" during a day of rallies and marches across the country.
Their camp outside St Paul's forced it to close for a week in late October for the first time since the Second World War.
It also led to the resignation of the cathedral's Canon Chancellor Dr Giles Fraser and then Dean of St Paul's, the Rt Rev Graeme Knowles.