What happened in the 1969 referendum that led Charles de Gaulle to resign?

In April 1969, President Charles de Gaulle called for a national referendum to vote on two constitutional amendments: the transformation of the Senate into an economic and social council and the reform of the regional structure of France.123

Seeking to reaffirm his leadership following the social and political unrest of May 1968, de Gaulle staked his presidency on the outcome, announcing that he would resign if the measures were not approved. The opposition seized this opportunity to challenge his authority. On April 27, 1969, the amendments were defeated by a margin of 53 to 47 percent. True to his word, de Gaulle resigned from office that night and retired to his country estate.123