The Day of the Jackal: WI Charles de Gaulle Assassinated in 1963

What would have happened if the plot to kill then President of France Charles de Gaulle described in Fredrick Forsyth's 1971 political thriller The Day of The Jackal not actually occurred but also succeeded?

In 1962 France was suffering from a wave of terrorist attacks, bombings and assassinations waged by a far right paramilitary group called the OAS. The group was comprised of French military officers and a significant number of French Foreign Legionnaires and other serving and former French military personnel angered at what they saw as capitulation by De Gaulle over the issue of Algerian independence and felt a strong sense of betrayal having just fought and long and brutal war against Algerian separatists.

Around 1954, native Algerians had embarked on a popular movement to liberate the country from French rule. The result was a protracted insurgency directed at French colonial interests including mainly attacks on French civilians and military units in Algeria.
France pushed back as hard as they could, throwing thousands of troops into a bitter, brutal counter-terror campaign. However, they were also mired in an equally brutal and costly campaign in French Indochina. As a result, their resources were badly strained and losses steadily mounted and the treasury depleted, with the catastrophic defeat at Dien Bien Phu, the French public became demoralized and pressure grew for the government to cut their losses. The government was effectively thrown out in 1957 and Charles de Gaulle rose to power on the promise of ending the Algerian war and bringing the troops home.
Many in the military had regarded this as another humiliation for France on the heels of the debacle in Indochina.
It is worth noting that unlike other nations colonial empires around the world France had always viewed Algeria as an integral part of metropolitan France as opposed to an overseas possession and well over one and a half million French citizens (Known as pieds-noirs) lived in Algeria before independence (making up a significant proportion of the population) and faced (and ultimately realised) the prospect of a mass exodus to mainland France following Algerian independence.

When it became clear that de Gaulle was serious about granting independence to Algeria a group of dissident high ranking French military officers had formed the OAS. They began a violent campaign with the aim of securing the French possession and stop de Gaulle's program to pull out of Algeria altogether.
At first, the violence was directed at the Algerian National Liberation Front and the greater civil population, with the aim of forcing a French military intervention. It worked.
The French mainland populace, however, were war weary and wouldn't buy into the OAS narrative. They backed de Gaulle when he declared a state of emergency and moved to negotiate an end to French rule in Algeria.
At that point, the OAS shifted to terrorism on French home soil, including several attempts to assassinate de Gaulle and the threat by a mutinous Foreign Legion battalion to carry out a direct airborne assault on Paris and several other major centres of Algerian resistance such as Metz in Alsace-Lorraine.

The book begins in 1962 with the OTL failed attempt on de Gaulle's life carried out by Lieutenant-Colonel Jean-Marie Bastien-Thiry in the Paris suburb of Petit-Clamart. Following the apprehension of Bastien-Thiry and various other conspirators, the French security forces waged a short but extremely vicious underground war with the OAS.
The French security forces were very effective in infiltrating the OAS allowing them to seize and interrogate the OAS operations commander, Antoine Argoud. The failure of the Petit-Clamart assassination, and a subsequent betrayal of the next attempt on de Gaulle's life and Bastien-Thiry's eventual execution by firing squad left the OAS completely demoralised.

After examining their few remaining options the surviving leadership of the OAS conclude that the organisation is too thoroughly compromised by French government informants and conclude that the only way to succeed in killing de Gaulle is to hire a professional mercenary from outside the organisation, who is completely unknown to both the French government and the OAS itself. After extensive inquiries they contact an English hitman (whose true identity is unknown), who agrees to assassinate de Gaulle.

Having agreed to do the job for the OAS the assassin is assigned the codename JACKAL meticulously prepares for and executes his assignment utilising a number of false identities as cover and commissioning a gunsmith to produce a custom made rifle and ammunition for the mission.
As "The Jacakal" completes his planning and preparations and makes his way into France and towards Paris he leaves behind a number of bodies including a forger (Whom he had hired to produce documents for one of his fake identities) who attempted to blackmail him for more money and a number of French civilians who had accidentally stumbled across evidence of what he was doing. Along the way to Paris "The Jackal" is forced to cycle through most of his false identities after he becomes aware that the French authorities are aware of his mission and are pursuing him.

The French authorities become aware of the plot to assassinate De Gaulle after investigating a number of bank robberies and concluding that the OAS is behind them (the OAS is forced to rob a number of banks to raise the money to pay the Jackals fee). This leads them to abduct and interrogate a the bodyguard of one of the OAS leaders and from him are able to uncover the bones of the plot but little more.
It is decided that the best way to proceed is by establishing the identity of the assassin and launch a nationwide manhunt. To this end a highly regarded police inspector is assigned to conduct the investigation and twice comes close to apprehending "The Jackal" but is thwarted by a combination of good luck on the assassins part and the assassin having been tipped off by an OAS mole within the French government.
Despite this the inspector correctly deduces that the assassination will be attempted in Paris on the 25th of August 1963 which will be Liberation Day which is the one day of the year when De Gaulle will definitely be in Paris and appear in a public place that the Jackal can have easily reconnoitred beforehand.
To this end a massive security operation is mounted to protect De Gaulle who is unable and also unwilling to not be present on that date and place.

On the 25th itself the Jackal, disguised as a one-legged French war veteran (with forged documentation) passes through the security checkpoints carrying his custom rifle concealed in the sections of a crutch. He makes his way to an apartment building (which he had previously reconnoitred and copied the key for) overlooking the Place du 18 Juin 1940 where de Gaulle is presenting medals to a small group of Resistance veterans.

In the book the plot fails after the Jackal misses his first shot when De Gaulle unexpectedly moves his head slightly at exactly the wrong moment and while reloading is killed by French policemen (including the inspector leading the investigation) who had realised that the "war veteran" who was allowed past a checkpoint may be their man and then being close enough to have heard the first shot burst into the room and shoot him.

"The Jackal" is subsequently buried in an unmarked grave in a Paris cemetery, officially recorded as "an unknown foreign tourist, killed in a car accident." The Jackals true identity is never discovered as the most promising leads turn out to be false and it is strongly implied that the whole affair was hushed up with the British Government in particular very keen to cover up the possibility that the assassin may have been British.

What if "The Jackal" had fired just a fraction of a second earlier and hit his mark before being subsequently surprised and shot himself by a French policeman?

What would be the domestic and global ramifications of the President of France and liberator of Paris being shot in the head (With an explosive round meaning things would be quite messy) while presenting medals in full view of the French public?

The French police would have been left with just an unidentified dead body of the assassin and little knowledge about him beyond the fact that he was hired by the OAS and was likely an Englishman. Furthermore the most promising lead regarding the mans identity would have just been proven false. During the story the French reach out for help in identifying the assassin from law enforcement agencies around the world. This leads Special Branch in London (The UK's counterterrorist police at the time) to investigate and ultimately uncover one of the "Jackal's" false identities. Due to circumstantial evidence Special Branch come to believe that the assassin may be a man by the name of Charles Calthrop and begin investigating his whereabouts and raid his home. This theory is proven false after the real Charles Calthrop is returns from a holiday in Scotland and thus proven to could not have been the "Jackal".
How would the French Government, police and security forces react to having been unable to protect De Gaulle or to even identify his killer?

How would the OAS have proceeded with their plan having succeeded?

Interestingly if real then De Gaulle's assassination would have taken place only a few months before John F Kennedy's assassination in November 1963 in Dallas. Assuming that the shooting of De Gaulle doesn't somehow butterfly this away what would be the global ramifications of both the President's of France and the USA being shot in similar circumstances within a few months of each other?
In the aftermath of France's withdrawal from Algeria did the OAS really have much of a game plan following their historical intended assassination of De Gaulle?
Were they ever interested in trying to provoke some sort of uprising or staging a coup or anything of that nature?