Some of the constiuents of the CAC-40 index have low exposure to the domestic market. Similar to major firms in the FTSE-100, some large French firms derive most of their revenues from markets outside of France. Hence stock performance of these firms is more dependent on overseas economies than France.
The following chart from a Bloomberg article earlier this year shows some of the CAC-40 exposure to the domestic and foreign markets:
Click to enlarge
Source: Déjà Vu as France’s CAC Harks Back to FTSE 100 Before Big Vote, Bloomberg
Disclosure: No positions