Tax optimization for succession (inheritance)

I would like to have advice for the preparation of a living estate.

My mother who is still alive would like to give me her properties (apartments and house for around 1.4 million euros).

What would be the best strategy so that this succession costs as little as possible, what would be the best optimization? One of the possibilities could be to give directly to my 3 children (minors) ?

I had thought of many strategies including the creation of an SCI with ownership dismemberment, …

Thank you in advance