C'est si bon (Korean: 쎄시봉; RR: Ssesibong) is a 2015 South Korean musical drama film written and directed by Kim Hyun-seok. It was released on February 5, 2015.

C'est si bon (French for "It's so good") was an acoustic music lounge located in Mugyo-dong, Seoul. During the 1960s and 1970s, the venue was very popular with Koreans in their twenties and thirties, who went there to listen to live music. Among the bands known for having played there was the folk music duo Twin Folio composed of Yoon Hyung-joo and Song Chang-sik; this film depicts the band's beginnings while including a fictional third member, Oh Geun-tae.