In 2014, the peacebuilding missions in Sierra Leone and in the Central African Republic (CAR) were ended. While the former was described as being a success story, the latter failed to construct stable and lasting peace in CAR since a war broke out in December 2012 and is still ongoing in 2016. This study proposes an analysis of these two peacebuilding missions, using Roland Paris' theory Institutionalization Before Liberalization, which stresses the importance of strengthening local institutions and making them able to manage the destabilizing effects of liberalization. By examining whether the UNIPSIL and the BINUCA waited until conditions were ripe for elections, designed electoral rules that diminished reward ethnic inclusiveness and promoted good civil society, the authors came to the conclusion that the variables ripe conditions for elections and good civil society seem to be essential for a peacebuilding mission to be successful.In 2014, the peacebuilding missions in Sierra Leone and in the Central African Republic (CAR) were ended. While the former was described as being a success story, the latter failed to construct stable and lasting peace in CAR since a war broke out in December 2012 and is still ongoing in 2016. This study proposes an analysis of these two peacebuilding missions, using Roland Paris' theory Institutionalization Before Liberalization, which stresses the importance of strengthening local institutions and making them able to manage the destabilizing effects of liberalization. By examining whether the UNIPSIL and the BINUCA waited until conditions were ripe for elections, designed electoral rules that diminished reward ethnic inclusiveness and promoted good civil society, the authors came to the conclusion that the variables ripe conditions for elections and good civil society seem to be essential for a peacebuilding mission to be successful