It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them) that he said: The Sunnah is that when a man sits, he should take off his shoes and place them by his side.
Benefits and Issues: The chain of narration of this report is weak. However, as per necessity and circumstance, shoes may be placed at one's side, but to call this a Sunnah is not correct.
Source: Fadlullah al-Ahad: Urdu Commentary on al-Adab al-Mufrad, Page: 1190