In June 1970, Tillon coauthored a paper titled "It is no longer possible to remain silent" with Roger Garaudy, Maurice Kriegel-Valrimont and Jean Pronteau. The paper condemned the party's policy during the upheavals in Czechoslovakia and France in 1968, the "normalization" in Czechoslovakia in January 1970 and the suppression of the extreme left. Tillon was thrown out of the PCF.