The incident occurred outside Southgate Tube Station and the former X-Factor judge has been released on bail until November.
The 27-year-old spent 23 hours in custody after failing a breath test after she crashed her £199,000 vehicle into a Saab.
While helping the police with their inquiries, Tulisa admitted she had a drink “20 minutes ago”.
If the “Sight Of You” singer is charged, she faces a crown court trial and could be jailed for up to two years if convicted.
An eyewitness said: “I heard the engine roar. It was so loud and high pitched I thought it was a motorbike.
“Then an instant later I heard a huge bang and thought straight away, ‘someone’s dead’.
“I was amazed no one was seriously hurt. I could see the couple in the other car looked really shaken up.”
He continued: “I was furious with the driver because someone could have been killed, then recognised Tulisa as I got to the Ferrari.”
A Metropolitan Police spokesman said: “Police were called following reports of two cars in collision. Officers and the London Fire Brigade attended. There were no reported injuries.
“One of the drivers, a 27-year-old woman, was arrested on suspicion of drink driving and was taken to a London police station.”