1. There'll be long queues to get your number
If you haven't managed to pick up your number - or “dossard” as they are called in France - on Thursday or Friday then be prepared to face long queues on Saturday. You could be standing for more than an hour or so, which isn't exactly ideal preparation for a 42-kilometre run the next day.
2. The weather forecast
3. Prepare for the slow start
When The Local's editor Ben McPartland ran the Paris Marathon a couple of years ago, he didn't get past the start line until a full 50 minutes after the starting gun was fired. This basically meant his hi-carb breakfast had all but been digested, he was starving and cold and only had a few wine gums to keep going.
"The organisers were trying out a staggered start, which was fine for those at the front, but a nightmare for those at the back. I could have had an extra hour in bed," he said.
Basically you need to take plenty of food to the start and even if the gun goes off, you might still have time to pop for a croissant and coffee in a nearby café.
Race veteran Kwame Amaning suggests starting as near the front as possible " to give yourself as much 'clean air' early in the race (even if it means loads of people will pass you)".
4. People will be weeing on the Champs-Elysées
The Paris marathon is probably the only time in your life you'll see French women squatting on the Champs-Elysées to take a pee.
The lack of toilets is often a real problem at the start of the race and you'll see hundreds of people relieving themselves on the City of Light's famous avenue. Either wear a nappy or don't be afraid to join them. You won't find a much more picturesque toilet in any city in the world.
5. The cobble stones can be dangerous
It's not fun running on cobbles especially if you have done all your training on nice flat roads, says marathon runner David Chambers. Have a little run on them the day before to get used to them, or just take it easy over the cobbled parts of the course.
6. There's a lack of atmosphere
Parisians don't really tend to turn out and support the marathon runners like the locals do in London or New York. As a result the atmosphere is fairly flat throughout the whole course.
There'll be parts of the course where there'll be no spectators at all, so don't expect any help from the crowd. Although with the number of charities supporting runners in Paris, the atmosphere is improving.
7. You should enjoy the scenery
What the Paris marathon lacks in atmosphere it makes up for scenery. Who needs crowds when you can run down the Champs-Elysées, around place de la Concorde and Bastille and along the banks of the River Seine.
If you can, try to enjoy the view. It's much better than from the bus tours!
8. Prepare for the woods
The course in Paris takes in two big woods - Bois de Vincennes on the eastern side of the city and Bois de Boulogne to the west. It's a good chance to run in the shade if it's hot and also to nip behind a bush to go the toilet, if you've been desperately holding it in.
Although if you're at the back of the field, be warned that the ground around these “natural toilets” in the Bois de Vincennes can become hazardously slippery and you don't want to pull a hamstring after all that training.
9. There will be cheaters
When you get to Bois de Vincennes, you'll notice a fair amount of people suddenly run across the grass. You'll initially think they are heading off to find a toilet, but they are in fact cutting off a big loop of the course.
It seems ridiculous to enter a marathon and cheat, but by the time you get to 23 miles, you'd probably wish you did the same. You'll only be cheating yourself of course.
10. There's a death march in the final few kilometres
"Prepare yourself mentally for the Bois de Boulogne," says Amaning. "For several kilometres from about 35km onwards there are no crowds urging you on. You would have hit the wall and you are going to have to summon all your mental strength then."
Undoubtedly the worst thing about the Paris course and the one most runners complain about is the fact the final few kilometres are through the Bois de Boulogne, where there are virtually no spectators, just when you need them the most.
It feels a bit like a death march. You just have to make it out of there in one piece and then you'll get a big roar right as you approach the finish line.
See if you can spot the funny folks handing out little glasses of wine near the end. Although you might be tempted, it's best to get across that line before you enjoy the tipple the city has to offer.