本文以我國與法國這兩個半總統制國家爲研究案例，探討國會與總統選制對半總統制憲政運作的影響。本文以「總統選制」、「國會選制」、「國會政黨體系」、「憲政體制（半總統制）」、「政府型態」等變項所構成的分析架構對此議題進行分析。由於總統選制與國會選制會共同塑造一國的國會政黨體系，不同的國會政黨體系與半總統制此一憲政體制相互搭配，會組成各種不同的政府型態，不同的政府型態則會展現出不同的政治效應，是故不同總統選制與國會選制對於半總統制憲政運作的影響，便可藉由這樣的分析架構來加以掌握。透過此一分析架構，本文得到以下發現：首先，法國2002年總統任期改爲五年之前，法國的總統與國會選制共同塑造兩大聯盟的多黨制；我國2005年立委選制改革之前，我國的總統與國會選制亦共同塑造兩大陣營的多黨制。其次，儘管兩國的政黨體系看似相近，但由於政黨體系中政黨凝聚力的差異，法國的國會選制與政黨體系將憲政體制塑造爲總理總統制，我國的國會選制與政黨體系則將憲政體制塑造爲總統議會制。第三，在兩國政黨體系與憲政體制的組合下，法國呈現換軌式的憲政運作模式，並形成「一致政府且聯合內閣」或「分立政府且聯合政府」（亦即共治）的政府型態；我國則呈現未曾換軌的憲政運作模式，並形成「一致政府且一黨內閣」或「分立政府且少數內閣」的政府型態。第四，在法國於2002年與我國2005年進行制度調整後，兩國的憲政運作模式逐漸趨同化，都將趨向形成總統、國會與內閣三者一致而由總統主政的局面，但由於兩國半總統制次類型的差異，一旦例外地出現總統與國會多數不一致的情況，兩國的憲政運作仍將有很大的差異。

This study explores how the parliamentary and presidential electoral systems affect the constitutional operation of semi-presidentialism by analyzing the cases of Taiwan and France. Our analytical framework is built upon the variables “presidential electoral system,” “parliamentary electoral system,” “political party system in the parliament,” “constitutional system (semi-presidentialism)” and “government type.” Within this framework, the political party system in the parliament is produced by the presidential and parliamentary electoral systems. Different political party systems, when combined with semi-presidentialism, will contribute to different government types that demonstrate different political effects. Therefore, the effect of parliamentary and presidential electoral systems on the constitutional operation of semi-presidentialism can be well grasped with this analytical framework. Our approach generated the following findings. Firstly, in France before the president’s term in office was changed to five years in 2002, the presidential and parliamentary electoral systems together formed a multi-party, two-bloc system in the parliament; in Taiwan before the reform of the legislative electoral system in 2005, the presidential and parliamentary electoral systems also together formed a similar party system in the parliament. Secondly, while Taiwan and France appear to have a similar party system, due to the difference in party solidarity, France’s parliamentary electoral system and political party system shaped its constitutional system into premier presidentialism, while Taiwan’s was shaped into president parliamentarism. Thirdly, in France, the combination of the political party system and constitutional system contributed to an alternating model of constitutional operation, and formed an “unified government with coalition cabinet” or “divided government with coalition cabinet”（so called cohabitation), in Taiwan, the combination of the political party system and constitutional system contributed to a non-alternating mode of constitutional operation, and formed a “unified government with single-party cabinet” or “divided government with minority cabinet.” Lastly, after France’s reforms in 2002 and Taiwan’s reforms in 2005, their models of constitutional operation gradually became similar, with the president, parliament and cabinet tending to be unified, and the president acting as the major leader. However, owing to the different subtypes of semi-presidentialism adopted by these two countries, there is still a great difference between their constitutional operation when the president faces an opposing majority in the parliament.