Kylian Mbappe and Radamel Falcao helped Monaco return to the Ligue 1 summit with a crucial win at Lyon.
Fans got into the Stade Geoffroy-Guichard ground 17 minutes into match against Rennes.
Matuidi's contract expires at the end of next season and the club recently proposed improved terms for the 30-year-old.
Liverpool and Arsenal have been linked with Lacazette, 25, who earlier this season said he felt "the right moment" had come to leave.
Radamel Falcao and Kylian Mbappe fired Monaco back to the top of Ligue 1 with a 2-1 victory at Lyon on Sunday.
Having been sanctioned for crowd trouble, St Etienne played to a 1-1 draw with Stade Rennes in an empty stadium.