Well, and then the police stops you and fines you for child endangerment and unsafe behaviour on the road. I'm not the overprotective kind, but this example is one of extreme recklessness.
Why is it not realistic at night? And umbrellas have been around for a tad bit more than 4000 years by now. I walked or took public transport to school on my own since I was 7 until I graduated from university.
However, that's the sort of legitimate delivery that's actually a lot easier if the roads are not so congested with people driving themselves to work in huge comfortable 4x4s.
You know you can do this on foot or on bike too right?
https://cupofjo.com/wp-content/uploads/2015/09/biking-three-...
Part of the idea of a walkable city is that everything you need - nursery, groceries, parks, schools, housing - is within a 15 minute walk.
For the centre of Paris that is easily achievable for many.