A civil solidarity pact is like a special promise that two people can make to each other. It's kind of like getting married, but it doesn't have to be between a man and a woman, and you don't have to have a big ceremony.
When two people make a civil solidarity pact, they promise to take care of each other and be there for each other, just like people who get married do. They can also get some benefits from the government, like being able to visit each other in the hospital, being allowed to make healthcare decisions for each other, and getting better tax benefits.
People might choose to make a civil solidarity pact if they don't want to get married, or if they can't get married for some reason. It's a way to show that they love and care for each other and want to share their lives together.