The body of PC Gordon Semple, 59, was found in a flat at the Peabody Estate, in Southwark Street, on Thursday - a week after he went missing.
Stefano Brizzi, 49, appeared via videolink at Bromley Magistrates' Court. No indication of plea was given.
He was remanded in custody to appear at the Old Bailey on 13 April.
Mr Brizzi is charged with murdering PC Semple at his flat at some time between 1 April and 7 April.
Wearing a grey prison issue tracksuit, he confirmed his name, age and address as he appeared next to a lawyer at Lewisham Police Station.
During the brief hearing, bearded Mr Brizzi told the court: "I'm an Italian citizen but a UK resident."
Following the hearing it emerged police are keen to speak to a man seen at Mr Brizzi's flat on 1 April - he was only there for one minute and did not go inside.
Det Ch Insp Cliff Lyons, who is leading the investigation into PC Semple's death, said: "I am keen to trace a man who went to Brizzi's flat in Southwark Street on Friday, 1 April at about 15:00.
"It is incredibly important that we speak to him."
PC Semple, from Greenhithe, Dartford was originally from Inverness in Scotland.
He had worked in banking before joining the Metropolitan Police.
A post-mortem examination was carried out on 8 April but the cause of death was not determined. A further post mortem has been scheduled for Wednesday.
A man has appeared in court accused of the murder of a police officer whose decomposed remains were found in a south London flat.