Street bumps are no longer allowed in France. Existing ones can stay, but cities can't create new ones.

Instead they create bottlenecks and turns to force cars to slow down.

You are likely referring to prefabricated rubber speed bumps, outlawed because the material becomes very slippery when wet, endangering motorcycles, scooters, and bicycles.

Asphalt and concrete street bumps seem to be legal in 30 km/h zones.

Here's an offer from Citroen which is free and "open to all 34000 French mayors via an online form": https://www.youtube.com/watch?v=f-AI70ImUgE