Abstract
In the historical context, the political parties of France underwent significant changes during the Fourth Republic. This was due to the reorganisations of the main political parties. Thus, in 1945-1946, three parties emerged at once: the Republican Party of Freedom, the Independent Republicans, and the Republican Group of Social and Peasant Action (later merging into the party of the National Centre of Independents and Peasants (NCSC). The electoral behaviour of political parties also influenced the party system of the Fourth Republic. The purpose of the study is to analyze the transformation of the French party system during the Fourth Republic, identify the causes of its instability, as well as determine the impact of the reorganization of political parties, electoral behavior of voters and political alliances on the functioning of parliamentary democracy and the strengthening of executive power. Artificially created political alliances and the politicking of political party leaders led to the collapse of government coalitions at the first crisis of domestic or foreign policy. The obvious discrediting of the regime in the most diverse strata of French society was in the hands of those political forces that fought to limit parliamentary democracy and strengthen executive power (Gaullism). The creation of various committees and commissions under the Government helped bring civil servants closer to representatives of the private sector and form the so-called technobureocracy. Thus, the unstable party system of the Fourth Republic manifested itself in the instability of the cabinets.