1. % of people in Paris going out to eat for lunch/dinner, and % who go to restaurants as compared to takeaway/supermarkets/bakeries etc.
population paris -> 3 Mio (wild guess) % eat outside per day, 30% (900.000), percent of those who actually go to a restaurant 50% (450.000)
tourists -> 300.000 in the city on a given day (1/10 of population) % eat outside 70% (210.000), % eat in restaurants 80% (approx. 170.000)
2. Overall target market: 620.000 people per day - define peak hours
Peak hours: 11:00 - 14:00 for lunch and 17:00-20.00 for dinner
concentration: 50% / 50% so 310.000 each
3. Avg. Number per group
Important to calculate the occupancy rate per table. Say on average, 3 people go to a restaurant together, Would mean there is a need for approx. 100k tables in the peak hours.
4. Avg. Time spend in restaurants
Say 1 hour, so a restaurant can serve 3 groups during peak hours
5. Avg. Tables per restaurant
Say a restaurant has on average 10 tables. This would mean during the peak hours 30 groups can be served which would mean 90 persons per restaurant in peak hour and 180 persons per day.
6. No of Restaurants
Take the 600.000 people from the beginning and divide by approximately 200 which would equal 3000 people per day
Sanity check: 3 Mio people and 3000 restaurants would equal a 1000 people per restaurant which would be quite high. Thus I would double my estimate to at least 6000 - which would indicate 500 people on every restaurant. This would be in line with my experience of smaller towns and even villages with around 20 restaurants per 10.000 people.