The only problem with this, is why was the U.S effectively blamed for this, when there were internal groups in France, such as the OAS, who effectively were the most probable group who wanted De Gaulle dead..?
(Basically, the assassination was OAS's revenge for President DeGaulle's support for Algerian independence, & the resultant exodus of French-Algerian emigres back to France, after Algeria became independent...).
Certainly after the Basiten-Therry debacle, in 1963, in which OAS assassins failed to kill DeGaulle, due to their using the wrong almanac (apparently they used a 1962 almanac) to determine when darkness fell, in order to ambush the Presidential convoy, & hence kill De Gaulle...
As a result of this blunder, which resulted in minor damage to the Presidential vehicle, & the "gutting" of many OAS cells as a result of DGSE (French Counter-Intellegence) retaliation afterwards, the OAS would have tried again, just to prove that they weren't jokes...
If this is the case, then they hired a far more competent & professional assassin, than the ex-military personnel used in the above attempt...