The man, who was questioned Thursday before being arrested on Friday, denied that he was responsible, but police say they are sure they have caught the right man.
According to the police, the 31-year-old aimed an air rifle with a telescopic sight at a parade of cars celebrating the football victory in the German coastal town of Bremerhaven.
A 19-year-old man was hit in the shoulder, a 21-year-old woman was hit in the hand, and had to be operated on in the same evening, and a 46-year-old woman reported on Monday afternoon that she had been hit in the stomach.
A ten-man team investigated the incident, and had been following the man for several days, until the breakthrough came during his questioning and a search of the man's apartment, from where he is said to have fired the shots.
No details were revealed about the man's motives.