An Egyptian, three Moroccans and a Syrian were detained on Friday over the plan to carry out the attack in southern Bavaria state, police and prosecutors said in a statement.
The Egyptian, aged 56, allegedly called in a mosque for an attack to be carried out on a market in the Dingolfing-Landau district “using a vehicle in order to kill or injure as many people as possible”, according to the statement.
The Moroccans — aged 30, 28 and 22 — allegedly then agreed to carry out the attack while the Syrian, 37, encouraged them.
Investigators suspect “an Islamist motive” for the plot.
All the suspects were brought before a magistrate on Saturday after their arrest and are in custody.
German authorities have been on high alert for attacks on Christmas markets after a car ramming attack last year on a market in the city of Magdeburg killed six and wounded hundreds.