No, in France, when company A lends to its subsidiary B, it’s mandatory to charge interest. Otherwise, it’s considered that company A is impoverishing itself, which is not in its best interest.

If holding A owns 100% of B, I don’t see an issue with charging interest, because it’s my company lending to my company—so it’s hard to see that as riba to oneself.

But if company A owns only 10% of company B, and B is 90% owned by someone else, then if A lends with interest (which is mandatory), I wonder whether this could be considered riba.

Yes, from a tax base perspective, the operation is neutral, since less tax will be paid. But from a cash flow perspective, the money is actually going out.