The 5% wasn't introduced in the 2023 Mining Code, it is the 2012 code:
The Malian private nationals pay the same as the state.
What is not clear in the 2023 code, (not that it matters to FFX/LLL now) the State's free participation is set at a minimum of 10% but indicates no maximum (or cap) and its participation can be increased by purchasing in cash up to an additional 20% (cash participation)