If you are seeing sprints in your Portfolio Plan with the wrong names (e.g Sprint 1, Sprint 2...) I'd suggest having a look at your Plan issues sources. When creating a plan you can select multiple types of issue sources (Project, Board or JQL), and to get the proper sprint information in your Plan you have to use (Scrum) Board issue sources.
You can find more details on Plan creation here, and details on how to edit your plan issue sources after the plan was created here.
Let me know if that works out for you.
Cheers,
Thomas
Note: I believe your question and the answer could be of value to other non-French community members, hence the answer in English. I hope that's fine by you :)
From the question:
The sprints displayed do not match with the one in my board
