You do know that you need to be arrested before you can be charged right? That's a pretty universal rule in criminal justice systems, including France's.

Except... it's not. Unless you're a danger to society, at risk of fleeing or not responding to a court's summon you wont be arrested.
Especially not for something Le Pen (allegedly) did, which is rather trivial and will probably end with a fine if even that. Why should the state spend time and money on an arrest if a mere court summon will do?

On the flip side you can absolutely be arrested before charges are ever brought to court, like when the cops catch you comitting a crime. Once they've got your personal details and the statements they need you may be released until you hear from the courts, again depending on whether you're a danger or at risk of fleeing.

Point being - a charge does not require an arrest, an arrest does not require a charge.

It's true that the President hasn't publicly involved himself but considering prosecutors answer to his office I feel like its reasonable to assume he was probably involved.

Is it? Is he personally involved in the prosecution of some random guy who stole candy? Is he personally involved in all of the crimes being charged across France every day?
Because considering prosecutors answer to his office it's reasonable to assume he's probably involved. In all of it.

That's absurd reasoning. If you want to proof that he was actually involved there then you need to do better than that.

So what happened is this:
The National Assembly (roughly equivalent to the US House of Representatives, legislative, not answering to Macron) revoked her immunity, a judge (judicative, not answering to Macron) then ordered an investigation and finally a prosecutor charged her.

HOW do you look at that and then say "Macron had her arrested"?