Depending on the type of SPVs used or of assets in which it will invests, as well as your personal situation (residency, existing portfolio, etc), you might be able to claim tax benefits. More specifically, in France,:
In a SAS, you might be able to invest through your PEA (plan épargne en actions) or to benefit from the "remploi-cession" (art. 150 0 B Ter CGI).
In a Société Civile, those tax treatments are not available.
However:
A SAS is subject to corporate income tax (generally, 25% on the positive results of the SAS but certain preferred mechanisms exist)
A Société Civile is not subject to corporate income tax and the results of the Société Civile are directly taxed in France at the level of its shareholders (whether French residents or not).
A more comprehensive comparison between the SAS and the Société Civile can be provided upon request by Roundtable.
Please note that this does not constitute tax advice. You should consult your own tax, legal, and/or accounting advisors to assess your personal situation.
In addition, Roundtable does not guarantee in any way that you will be able to benefit from any tax exemptions or benefits.