Fourth Republic elections were held under a system of proportional representation with multi-member constituencies. However, when confronted with the particular threats of Communism and Gaullism, the parties of the majority introduced complicated arrangements for the 1951 election. The eight constituencies in the Paris region (i.e. Seine and Seine et Oise) were the areas of greatest strength for Communism and Gaullism. Consequently, the electoral law laid down that these constituencies should be fought under a system of proportional representation by the largest remainder (this system favoured small parties). In the rest of the country, apparentements were permitted. This system allowed ‘national parties’ (defined as parties that fielded candidates in at least thirty constituencies) to sign agreements with each other before the election. If any single party or group of parties united by an apparentement agreement gained more than 50 per cent of the vote in a constituency they then took all the seats. If such a result was achieved by a group of parties in an apparentement agreement, the seats were then divided among them in proportion to the votes that each had obtained. If no party or group of parties gained more than 50 per cent of the vote the apparentement agreement could still prove beneficial. Any party within an apparentement agreement that failed to gain enough votes to elect a deputy, would then see all its votes transferred to its allies.