How to enforce shoes removal in a lobby/house?

I just moved to a new flat, and I've a personal habit of removing my shoes when entering my flat, similar to the custom in some Asian cultures. This is in order to keep the house clean, and feel the ground with my feet :)

My previous flat had a smaller and less open hallway, so that it was helping to enforce this rule even to guests. On the contrary, the new hallway is bigger and open to the living room and corridor. So there is a lack of guidance here, and people can spread everywhere.

Context

I live in a French city, and many of my guests are familiar with Japanese culture, at least peripherally through things like anime, manga and games. I'm keen to think that either living in a city doesn't entice people to remove their shoes, or that the small hallways don't help either once people have already entered the flat.

Question

How can I design my lobby/entrance so people are aware that removing shoes is requested?

N.B.: I'm living in Europe where there is no such etiquette.