Hi there!
I know I am a little bit late to the conversation, but I think I can give you a little bit of more information.
Five friends of mine went to Sciens Po for their Year Abroad in 2019/2020, 3 to Paris and the other 2 to Reims and Strasbourg.
The girl who went to Reims had a wonderful time there, stayed in an ensuite in a private student accommodation building and spent a lot of time in and outside University with her French and Study Abroad peers. At first she was a little disappointed she wasn´t chosen for Paris, but when she realized how much money she was going to save she cheered up.
As for the girl in Strasbourg, she was better integrated with her French peers than with her Study Abroad ones, mainly because of her classes schedules. She rented a room in an AirBnb hostel and made lots of friends. As per the costs, it was a little bit more expensive than Reims.
The 3 girls who went to Paris had a really different experience. They rented an apartment with another Study Abroad girl in order to have more habitable space, but it was pretty expensive, even considering their accommodation was 50 minutes away from Sciens Po by Metro! They spent their time with other Study Abroad students, as regular students didn´t integrate them to their socials or other events. When they were invited by regular students, it was for really expensive socials (the minimum cost was 80 euros, if they wanted to spend less, they were excluded). Despite this, the three of them consider their year abroad as a really positive experience.
@Delphigirl Is any other student from your DS course willing to apply to Sciens Po as well, so they would go to the same campus?