“Tirer les boulets rouges à quelqu’un” is a French expression that translates literally to “to fire red balls at somebody”. English meanings include:
- to rip into somebody
- to give somebody both barrels
- to lay into somebody
The idea here is that when somebody gets very angry at somebody else, he or she fires red-hot cannon balls into them. Expressio.fr offers a great French definition: to attack somebody else with violent terms; to rain on somebody with insults and criticism.
Son ancienne patronne lui tirait des boulets rouges sans cesse. Elle a fini par le virer. His ex-boss laid into him non-stop. She ended up firing him.