let me share my knowledge here,
shareholders of TOTAL can be A,B,C,
A,B,C can be companies or individual people. If A is a company, A might have shareholders as well, so shareholders of company A will not make decision for TOTAL, but can make decion for company A. Therefore only company A can make decision for TOTAL. and not shareholders of company A.
also, if CA is second largest shareholder of amondi other shareholders can go againts CA during voting, for example CA hold 30% of amondi, the other 70% holders can simply go against CA during voting and win the decision