Jakob Ingebrigtsen was first over the finish line and seemed to have secured the gold.
But on the results lists, the 20-year-old was placed in last place - after being disqualified.
Instead, Polish Marcin Lewandowski was the winner.
Ingebrigtsen's father and coach, Gjert Ingebrigtsen, quickly submitted a protest, and was upheld by the competition jury.
A few minutes before midnight, the gold was Norwegian again, writes NRK and VG, with reference to the Norwegian Athletics Association.
The controversial event occurred in the first turn, when Ingebrigtsen ended up in trouble and off the list.
- The rules are on my side.
I do not think I did anything wrong, it was just too many runners with, says the runner to NRK before he was told that the gold has become his again.
The victory time was 3.37.54.
CLIP: European Championship silver for Fanny Roos
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Fanny Roos sets Swedish record and takes European Championship silver