Police were tipped off by the man's neighbour that he was stockpiling a large quantity of pyrotechnics.
Officers descending on the man's home found the fireworks packed into his apartment, cellar and two vans, a police spokeswoman told national news agency DPA.
The pyrotechnics contained around 80 kilos of explosive substances — 80 times over the limit of fireworks that can be legally stored in a private home.
Fireworks and rockets are an essential part of New Year's festivities in Germany, with revellers firing off huge amounts of pyrotechnics from balconies or their lawns.
They are sold on the last three days of the year, with people in Germany spending 137 million euros ($156 million) on them last year.
But January 1 is also marked by casualty reports of individuals injured or even killed by fireworks.
On New Year's 2018, pyrotechnic mishaps left two people dead, a child injured and five people requiring amputations.
This season, several injuries have already been reported even before New Year's eve, with two people including a 14-year-old losing fingers to firecracker blasts gone wrong, while an 18-year-old was hospitalised for severe burns.