John Phillips, father of MacKenzie and leader of The Mamas and The Papas (John, wife Michelle, Denny Doherty and Cass Elliott) composed "San Francisco (be sure to wear some flowers in your hair)" for Scott McKenzie. They were both in the group The Journeymen at one time. It was never recorded, as far as I know, by either John or The Mamas and The Papas.
Johnny Hallyday (Jean-Philippe Smet), popular French rocker hit with the song in 1967 in both France and Quebec.
Scott McKenzie's (Philip Wallach Blondheim) chart topper came in 1967. It features John Phillips on guitar. He and John helped compose the Beach Boy's "Kokomo". Scott composed Anne Murray's first release "Hey, What About Me" in 1968. Perhaps it's interesting to note that Scott failed in his audition for The Monkees.