When Davis looks through the telescope after leaving lunch, the view of the telescope follows the people walking. Davis did not move the telescope to follow them, it was in the same position after the view returned to Dabis.
When John picks up Millie to drive her to ballet class and they are at and in the car, a man in a yellow shirt wearing a hat can be seen in the background parking his white bike twice.
When the estate agent shows the villa to M.Pimm she quotes the monthly rental at 7,500,000 francs. In 1963 at the exchange rate of 4.901 francs to the US dollar that would be the equivalent of 1.53 million US dollars per month. In 1963 that villa may have been valued at 1.53 million but would hardly have rented for that much.
Up to the introduction of the Euro EUR, many French people still counted in and spoke in "anciens francs." So 494 anciens francs were worth 4,94 nouveaux, or the number of anciens francs divided by 100. The "nouveau franc" was introduced on 1 January 1960. In this case 7.5M anciens francs would equal 75,000 nouveaux francs or $15,303, a much more reasonable amount.
When Millie and Davis first go to the lookout where winning drivers are commemorated, Mille reads out some of the drivers' names. One of these is 'Brabham", but she mispronounces the name with a long 'a' as 'Braybham' rather than with a short 'a' as in 'cat'.