Allan’s right. When we drove to France regularly when the kids were little it became law to carry a breathalyser kit in the car. The kit we carried was about the size of a cigarette packet & contained 2 breathalysers. It cost about £2 & was single use like the original bag type the police used when they first came out. I always thought they were a bit pointless because the idea was to self test & I thought it would actually encourage drink driving, you have a drink or 2, test yourself negative so drive even though you’re impaired. I’m not sure if it’s still required in France I recall there was talk of doing away with it several years ago.

@Allan C. Have you checked the expiry date on yours as part of the law was the kit had to be in date.