The President also has the right to refuse to sign ordinances and decrees discussed in the Council of Ministers concerning the appointment of senior officials. Apart from these, all other decrees are made by the Prime Minister on his own. These powers cannot be considered substantial by any means; they are exceptional in the sense that they are not the type of power that will be exercised in the day to day running of a government - they can only be invoked periodically, and the majority are not powers of decision, but correspond to the concept of the major part of the President's role as one of arbitrator as laid down in the constitution. He can prevent decisions passing in order to subject them to fresh examination and have their legitimacy checked, or he can submit them to a referendum.
These powers are clearly not what de Gaulle was after in writing the constitution, so why not explicitly lay down that the President would be the head of the executive, set out precisely what powers he should have from the start, and not have to go through the process of assimilating power over the course of the next few years? The answer lies in French history, which is littered with warnings of the dangers that were associated with creating too powerful a figure as the head of the political system, namely violence and disruption. Undoubtedly the turmoil associated with Bonapartism was a factor that meant a strong President might not be accepted, but more recent history, as shown by Pétain's regime during the occupation, also occupied a large part of the mass consciousness, less than fifteen years after the end of the war. Thus de Gaulle realised that it would have been difficult to establish a completely presidential system, and he settled for "sharing" power with the Prime Minister, and being elected by an electoral college. De Gaulle would not accept being elected by the parliament as he hated the institution, but could not push for election by universal suffrage, as the last time that had happened, Louis-Napoleon Bonaparte had won and set himself up as Emperor.