Police were called out to the apartment on the Stora Essingen island in the Swedish capital at around 8.30pm on Sunday, after loud noises and arguments were heard coming from inside.
Swedish tabloid Aftonbladet reports that a man barricaded himself in the apartment when police arrived and refused to come out. Two other people who were also in the apartment managed to get out.
At around 11.20pm police fired a shot and the man was taken to hospital.
Aftonbladet reports that he was wounded in the leg, but police declined to comment on where he was hit. However, they said his injuries were not life-threatening.
Police declined to say if the man was armed or if he had been violent towards another person, but said that he was alone when he was apprehended.
The man, who is in his 40s, is currently being held on suspicion of preparing to commit murder.