commencera

It has to do with the concept called the 'immediate/concrete future and the  practice in dialog form of using  Le Present. I am not sure if it apples in formal writing.

KWIZ  has a lesson on it called Using Le Présent for immediate/near future actions.

Couple examples from that lesson are : Demain, il arrive à dix heures./Tomorrow, he's arriving at ten o'clock. and Je prends mon train dans une heure./I'm taking my train in an hour.

I added the term concrete for my clarity... but you can see the concept that while the action of the verb is technically in the future and is not 'accomplished'... the sense is that it is a 'done deal' and does not really hang on a 'future plan' of action.

One nice example I have seen is where in English we say, "We'll see each other tomorrow" , the French  translation is " on  se voit demain".. the present tense and generic 'on'.

I don't think it overrides the 'technical' use of the future (you weren't be marked wrong I don't think) but it makes you look, to use a galling but not Gallic term, "as if you didn't just hit town".

Thanks Jameson, that was a good explanation.