The Prophet (ﷺ) led them in praying Zuhr with five (rak'ahs). They said: 'You prayed five.' So he prostrated twice after he had said the taslim, while he was sitting.
Sunan an-Nasa'i Book 13, Hadith 77
← Previous Hadith "The Prophet(ﷺ) prayed Zuhr with five rak'ahs, and it was said to him: 'Has something been added to the prayer?' He said: 'Why are you asking?' They said: 'You prayed five.' So he turned around and prostrated twice."

Sunan an-Nasa'i Book 13, Hadith 76 Next Hadith → "Alqamah prayed five (rak'ahs) and was told about that. He said: 'Did I really do that?' I nodded yes. He said: 'What about you, O odd-eyed one?' I said: 'Yes'. So he prostrated twice, then he narrated to us from 'Abdullah that the Prophet (ﷺ) prayed five (rak'ahs), and the people whispered to one another, then they said to him: 'Has something been added the prayer?' He said: 'No.' So they told him, and he turned around and prostrated twice, then he said: 'I am only human; I forget as you forget.'"

Sunan an-Nasa'i Book 13, Hadith 78