To assume that Charles de Gaulle did not impact today's political policies in France is a lost notion. Without de Gaulle, there would likely not be nuclear technology, and thus a very different nuclear policy. Without de Gaulle, France would likely not be as influencial as it is within the UN. Foreign policy would then be completely restructured. A man that has had so much influence on the country in its entirety must be considered as the reason there is even a policy at all.
Yes, I think that Chales de Gaulle's leadership of the Fifth Republic was responsible for France's current policies, because de Gaulle was very influential. De Gaulle led the people through their yearning for more individual freedom, but also helped them to recognize their past that was rich in a strong social safety net.
It is hard to say exactly what in the past has truly impacted on the present, however I think that Charles de Gaulle's leadership did help to shape France's current political policies. Without Charles de Gaulle the country would look like a very different place and would have different policies.
Charles de Gaulle saw France through tense Cold War years in the 1950s and 1960s. Part of his leadership saw the fall of Vietnam as colonial France lost its final hold on southeast Asia. France needed extra help from the United States to try to repel the Vietcong. De Gaulle did as well as he could, considering the circumstances of his presidency.
No, I do not think that one man's leadership led to the current policies that France uses. They have had a long history, like the United States, in finding freedom and finding out a way of governing that works and supports the people in a way that is fair and just.