It was falsely reported by some on Twitter that the 32-year-old had died, but the club acted quickly to deny these reports.
Lyon released a tweet which read: "Mathieu Valbuena is happily alive and well contrary to what those despicable individuals are spreading on Twitter".
"Lyon are horrified at such disgraceful and inhuman acts," the club added.
Valbuena has been at Lyon for two seasons and has played 42 times for the Ligue 1 club.