The incident on Monday shook Germans still struggling to take in last week's racist gun attack on two bars in the town of Hanau, which left 11 people dead.

The Kassel district court ordered the suspect, a 29-year-old German man, remanded in custody on suspicion of attempted murder, grievous bodily harm and dangerous interference with road traffic, a spokesman for the prosecutor said in a statement on Tuesday.

"The accused is suspected of having deliberately steered his car into a large group of people with the intention of killing ... during the Rose Monday procession in (the town of) Volkmarsen," the spokesman said.

Rose Monday is the height of the carnival season in Catholic areas of Germany, especially in the Rhineland where tens of thousands of people dress up, drink alcohol and line the streets to watch decorated floats that often mock public figures.

The 61 people injured - some of them seriously - were aged between two and 85.

Investigations into the driver's motive were continuing and all possibilities were being investigated, the prosecutor's spokesman added.

An emergency responder said bystanders had punched the man while he tried to choke her as she leaned into the car to remove the key after his vehicle crashed.

"He didn't say a word. He looked at you empty and dead and seemed so satisfied," Lea-Sophie Schloemer told Welt television.

"It was really unnerving how satisfied he seemed."

Initial tests for alcohol were negative but that was not a final assessment and there were as yet no results from the drug test, the prosecutors' spokesman said.

Australian Associated Press