Pollice were called to a flat on Sherwood Rise, Nottingham, just before 3.30am, on November 22, last year, and saw Caro Sango trying to warn party-goers that officers had arrived.
They tried to identify the occupants of the flat and found Sango's passport in a bedroom, said prosecutor Robert Carr.
He told them he only expected 17 people to turn up originally but around 50 attended.
Sango accepted full responsibility for the party and was given a fixed penalty notice for £200, but he failed to pay it, Mr Carr said.
The student, who represented himself, told magistrates he wasn't the organiser but ‘accepted responsibility for the party’ as his flat mate was away at the time.
He said the fixed penalty notice was probably sent to his home address in London.
Sango, who has no previous convictions, made full and frank admissions to police and entered a prompt guilty plea.
The university has already imposed a sanction on him, he told the court.
Sango, 22, of Sherwood Rise, pleaded guilty to participating in an indoor gathering, when he appeared at Nottingham Magistrates Court, on Wednesday, March 10.
He was fined £220, and ordered to pay £85 towards costs and a £34 victim surcharge.
The court heard he could have been liable for an unlimited fine under the new legislation.