According to reports on Wednesday, the singer is accused of infecting three people. At least one man has been diagnosed with the HIV virus.
Benaissa, 26, a mother of one, became a celebrity overnight when she and four other young women won the first German series of reality TV show Popstars in 2000 reported The Daily Telegraph.
They formed No Angels, who were said to have been modelled on the Spice Girls, and went on to have a string of No 1 hits. The group split in December 2003 before four of the original five members, including Benaissa, reformed in 2007.
Benaissa was arrested in Frankfurt on Saturday evening, shortly before she was due to give a solo performance. She was remanded in custody after a judge ruled there was a danger she might repeat her alleged offence.
The public prosecutor's office in the western town of Darmstadt said the singer was being held because of the "urgent suspicion that the accused had unprotected sexual intercourse with three people in the years 2004 and 2006 without telling them beforehand that she was HIV positive".
If found guilty she could face up to 10 years in prison reported The Daily Telegraph.
