His computer contained a search history of potential targets.
The Paris prosecutor's office described him as "psychologically unstable but conscious (of his actions) and determined".
The arrest took place on Thursday and the man was charged on Saturday for individual terrorist activity and remanded in custody, The prosecutor's office said that the suspect's plans were vague and not yet finalised, and that he appeared to be acting alone.
He did, however, tell police of a possible plan to attack Macron on July 14, when the French president traditionally attends the annual military Bastille Day military parade on the Champs-Elyées, and expressed "nationalist" views.
According to RMC, he said he wanted to make a "political" statement by killing Mr Macron, and said he wanted to attack "blacks, Arabs Jews and homosexuals".
The suspect was convicted last year to three years in prison, with 18 months suspended, for "provoking racial hatred and supporting terrorism" after expressing admiration for Anders Behring Brevik, the Norwegian far-Right terrorist who murdered killed eight people in a bomb attack and shot dead another 69 Workers Youth League members at a summer camp in July 2011.
The French suspect's chatroom request for a Kalashnikov-style weapon was reported to a government terror alert site called internet-signalement.gouv.fr.
This is not the first time police appear to have foiled a Bastille Day assassination plot on a French president.
In 2002, Maxime Brunerie, a far-Right neo-Nazi tried to murder then president Jacques Chirac with a long-range rifle before being overpowered by members of the public.
Sentenced to ten years in prison after saying he had hoped for a "glorious death", he was released in 2009.
Mr Macron will oversee a military parade in Paris on July 14 alongside President Trump on the Champs-Elysees, where US soldiers will march alongside French troops to commemorate the centenary of the US entering the First World War.
He will then head to Nice to mark the anniversary of the Islamic extremist truck attack that killed 86 people in the southeastern city.
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