(FILES) In this file picture taken on September 27, 2015 a man holds a placard reading « Congo is not the property of N’Guesso » during an opposition demonstration in Brazzaville . Tensions were rising sharply between youths and police in the southern districts of Brazzaville on October 20, 2015 , after the banning of an opposition rally ahead of the referendum on October 25, 2015 that could allow President Denis Sassou Nguesso to stand in 2016. AFP PHOTO / LAUDES MARTIAL MBON