Anas Radiyallahu 'Anhu says:
"A person who was wearing yellow coloured clothing was sitting by Rasulullah Sallallahu 'Alayhi Wasallam. It was the habit of Rasulullah Sallallahu 'Alayhi Wasallam not to bluntly express things he did not approve of. (Therefore he kept silent). When that person left, Rasulullah Sallallahu 'Alayhi Wasallam said to those present 'It would have been better if you had told him not to wear yellow clothing'".
English reference: Book 47, Hadith 329
Arabic reference: Book 48, Hadith 346