It is reported about Sayyiduna Uthman bin Affan (may Allah be pleased with him) that he saw a funeral and stood up. Then he said: "I saw the Prophet (peace and blessings be upon him) see a funeral and stand up for it."
Ahmad and al-Bazzar recorded it. Its chain contains a narrator, Musa bin Imran bin Mannah; I did not find anyone who has given his biography in a satisfactory way (i.e. one that meets the need).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الجنائز / 4110