Prosecutors did not name the company, but an Aurubis spokesperson confirmed separately to Reuters that it is the producer involved.
Aurubis, Europe's largest copper producer, has cut its earnings forecast for its current financial year and suffered a fall in its share price following major suspected metals theft.
A statement from the Hamburg state prosecutors office said five people had been charged in connection with the theft of about 5,000 kilogrammes of materials containing precious metals from the company between February 2020 and January 2021. A further person has been charged with assisting them.
Precious metals including silver are contained in copper ores and scrap which are refined for sale as by-products by Aurubis.
The stolen material was allegedly sold to as-yet unidentified parties but part of it was sent for analysis and further used by an unidentified company in Turkey, prosecutors said.
The five people, aged between 33 and 50 years, used encrypted mobile phones to communicate with each other. Their trial is scheduled to start in December, prosecutors said.
($1 = 0.9189 euros)
(Reporting by Michael Hogan, editing by Josie Kao)