Migration Ms Access DB -> MySQL

I am investigating a bit how I could migrate an Access Database (with arround 1 hundred of tables, and millions of rows) to a MySQL DB

I can do it 1 table by 1 table in Ms Access (slow) and the schema is not well migrated,
- no index
- no primary key
...

Does someone has a free tool (or code) to do such migration, keeping a maximum of the structure ?
I tried several small softs, but haven't found something suitable yet.

Thanks a lot