This is from a set of ISDS proposals for the TTIP from Jan Kleinheisterkamp and Lauge Poulsen:
Comprehensive state ‘filter’ of private claims
Our second patch is that home and host states should be allowed to block individual claims, if they both agree the dispute should be settled by domestic judges rather than international arbitrators. A similar option is included in NAFTA for investment disputes regarding tax questions with the justification that it can block particularly controversial investor disputes from proceeding. In CETA, as well, there is a similar filter mechanism for investment disputes in financial services.
Extending such filter mechanisms to all areas covered by the investment provisions addresses fundamental concerns about safeguarding public policies. Taxation and financial stability are important issues, but so are environmental protection, health concerns, consumer protection and other public interest matters. The Hong Kong government would likely have agreed to block Phillip Morris’ recent claim against Australia, for instance, if a filter mechanism had existed in the relevant treaty.
Is this the kind of tweak that would satisfy the French and the Germans?
In a joint declaration, the ministers of the EU’s two largest economies asked the European Commission, which steers trade negotiations on behalf of the 28 EU member states, to examine "all the options for modifying" the ISDS clause in the agreement with Canada.