Paris-Lyon is the busiest High-Speed Line in Europe and has been open to open access competition since 18 December 2021. The purpose of this article is to explore the first effects on the price and frequency of competition between the Italian company Trenitalia and the French incumbent SNCF. The analysis is based on a large database (n = 971) collected from September 2019 to July 2022. The main challenge is to isolate the COVID-19 pandemic effect from the competition. A similar route without competition (Paris-Bordeaux) was selected to control the effects. The method relies on a descriptive analysis with an original dynamic timetable approach in the discussion. The results highlight an increase of frequency by 5% and a decrease in price by 10%. The prices charged by the newcomer are lower than those of the incumbent (-30% to -40%) though without enough volume to change the global equilibrium. Although far from a big bang, the comparison with the control route suggests a positive effect on price that moderates the economic catch-up effect following the COVID-19 pandemic in an inflationary context. More specifically, SNCF appears relatively insensitive to competitive pressure from Trenitalia. It has not significantly changed its price since the new offer was introduced and has maintained its trains.