Always double-check your work.

The programmer in charge of a computer with the job of issuing traffic citations goofed in September, 1989. The computer sent notices to 41,000 residents of Paris, France informing them that they were charged with murder, prostitution and illegal sale of drugs.

Here’s more about that mistake

What Happened

The Paris judicial system had recently automated its automated notice and collection system. Instead of generating routine notices for minor parking violations and traffic infractions, a bug in the code cross-indexed or misaligned the offense code database.

Rather than pulling the text strings for minor driving infractions (like illegal parking, speeding, or running a red light), the system pulled charges from the severe criminal code database.

The Aftermath

Over 41,000 residents opened official, sternly worded legal summonses from the Ministry of Justice informing them that they were under investigation or charged with major crimes—including:

Murder and manslaughter

Organized prostitution

Extortion and blackmail

Illicit drug trafficking

As you can imagine, the mistake caused widespread panic, outrage, and chaos at local police stations and court houses as thousands of bewildered drivers showed up trying to clear their names of hitman-level charges when they had simply overstayed a parking meter.

French officials quickly issued public apologies, clarified that it was a technical glich, and assured residents that no felony charges were actually being pursued. It remains a legendary classic example in computer science and IT history of what can go wrong with early automated database management.