Food marketing, particularly for products of low nutritional value and high energy density, is part of the obesogenic environment that is driving the global obesity epidemic among adults and young people. The main objective of this study was to quantify children’s and adolescents’ exposure to advertising for fatty, sugary, and salty (FSS) products, and how this exposure has changed, particularly on television. In this context, the number of television commercials for FSS products aired and viewed by children and adolescents in 2015 and 2018 was calculated. The study also provided data from 2012, 2015, and 2018 on trends in media devices and usage, as well as food advertising spending, particularly for FSS products. This study focused on children aged 4–12, adolescents aged 13–17, and adults aged 18 and older. Data on media devices and usage were collected through studies by Médiamétrie and Ipsos. Data on advertising spending were collected by Kantar Media. Coding based on the nutritional quality of advertised products was performed by Santé publique France. Two nutritional profiles were used for this purpose: the Nutri-Score and the WHO nutritional profile, to ensure European comparability. Quantifying exposure to television advertisements for PGSS required combining Médiamétrie’s audience data with Kantar Media’s data on the days and times of broadcast for advertisements and sponsorships of food products and brands. In 2018, television remained the most-watched medium among children aged 4–12 (1 hour and 28 minutes per day) despite a decrease in viewing time. Their internet use, however, increased, reaching 53 minutes per day in 2018. Teenagers spend 2 hours a day online and 1 hour and 12 minutes watching television, which is 42 minutes less than in 2012. The time slot between 7:00 PM and 10:00 PM (prime time) is the most watched, by adults as well as children and teenagers. The TV shows most watched by children and teenagers are dramas and entertainment programs, which are primarily broadcast between 8:00 PM and midnight—one of the time slots with the highest volume of advertising. Thus, although the time spent watching television by children and adolescents has decreased, the daily time spent viewing advertisements between 2012 and 2018 increased, rising on average from 7 minutes to 9 minutes per day. Another notable finding is that children’s programs—which are currently subject to advertising bans on public channels and self-regulatory measures by the food industry—account for 0.1% of all programs aired and less than 0.5% of programs watched by children. Regarding internet use, the most common activity among children and adolescents is watching videos, followed by social media use among adolescents. Numerous advertisements are displayed on these websites and social media platforms, but it is currently impossible to estimate children’s and adolescents’ exposure to digital marketing due to a lack of reported data on investments and targeting. Advertising spending on food products (including food, beverages, and restaurants) across all media totaled €1.1 billion net and accounted for 9.3% of the estimated total net advertising market spending in 2018. According to estimates provided by the Dentsu agency, the majority of these investments were made in television (60%) and online (20%) in 2018. This dominant share of television investments is a distinctive feature of food advertisers, who invest more in television than other market players. The share of television has nevertheless decreased compared to 2012 (63%) and 2015 (67%), primarily due to an increase in online advertising spending. Fast food, chocolate, and sugary drinks are the three sectors receiving the largest share of food advertising spending. They account for one-third of this spending. Advertising spending across all media for Nutri-Score D and E products—that is, those of lower nutritional quality—accounted for 48% of food advertising spending in 2018. Finally, key findings measured for the first time in France: the advertisements viewed on television by children, adolescents, and to a lesser extent by adults are predominantly for products with Nutri-Score D and E ratings. In 2018, these advertisements for Nutri-Score D and E products accounted for 53.3% of food advertisements viewed by children, 52.5% of those viewed by adolescents, and 50.8% of those viewed by adults. 87.5% of advertisements for Nutri-Score D and E products are viewed during times when more than 10% of children and adolescents are watching television; half are viewed between 7:00 PM and 10:00 PM, a time when more than 20% of children and adolescents are watching television. These findings support restricting food marketing for products of low nutritional quality, particularly on television, during the hours when the largest number of children and adolescents are watching television. Furthermore, the increase in time spent online by children and adolescents suggests a much greater exposure to advertisements for PGSS, although it is not yet possible to measure this; however, regulation appears equally necessary.