You’ll pay 8% of your income (that the French government is allowed to tax, after an additional standard deduction of around $11,000 per person). As a ballpark figure, an individual who has income to declare to the French government of $30,000 will pay around $1,520 a year in healthcare.
However, you are also only reimbursed 70-80% of your costs (depending on what it is), similar to the NA system(s), where your employer health plan may only reimburse a percentage as well but where no 'top-up' exists.
In order to make up the remaining amount in excess of the 70% reimbursement (80% for hospital stays), many French residents opt for private, or “top-up,” insurance. Several options exist, and rates vary from $36 to $72, on average, per month
Let's take France. Looks like it's 8% you pay:
However, you are also only reimbursed 70-80% of your costs (depending on what it is), similar to the NA system(s), where your employer health plan may only reimburse a percentage as well but where no 'top-up' exists. https://internationalliving.com/countries/france/health/