Every time I'm trying to order my SIM with my French credit card it says that the CVV looks incorrec

Chloé

You can use only canadian credit cards

You can use a Visa or MasterCard credit card to pay for your Fizz plans.
- including Visa or MasterCard prepaid cards which accept recurring payments
- including also Debit MasterCard or Visa Debit card
.
Other cards such as debit cards, American Express (Amex), Dinners, and others are not accepted.
Foreign credit/debit cards are not all accepted.
You also cannot use the funds from your Fizz Wallet to pay for your monthly plan.

source: https://fizz.ca/en/faq/what-payment-methods-can-i-use

You can have an online credit card, KOHO it is accepted

If there is a partipicating Couche-Tard near you, you can get a Fizz SIM card for free (until January 4 2021 while supplies last): https://fizz.ca/en/couche-tard-sim

You just need to install the Couche-Tard app, enter your email and wait until you are at the cash abd ready to pay before using the electronic coupon. The Fizz SIM card will be free!

This is also a good time to join Fizz as they are giving $50 bonus credit to new customers (until January 6 2021).

If you need a referral code, there is a list here:
https://community.fizz.ca/questions/2198337-place-referral-codes
You can choose mine, both parties will receive the bonus credit once you have paid your second bill.

I think you can't order with a french credit card.

@StefanM check the link provided by Mike and you will see that you can't use foreign cards. If yours worked, it was just a bug.

@Yolo
I can only share what I experienced :-) It worked for me even with my old plan. Never had any problems. I even switch from my Canadian to European credit card because it offers me better cashback.