The Euro is not fixed to anything, but its value floats freely like any other currency. It is "fixed" to Eurozone members in the sense that they can't value/devalue it by themselves.
Comparing the Bretton Woods system to the Eurozone is not a direct comparison
Fixed exchange rate meant as if all countries in Europe would have a fixed exchange rate between them (even if they would use different currencies). Hence the comparison eurozone-Bretton Woods
Comparing the Bretton Woods system to the Eurozone is not a direct comparison