Those are arbitrary figures, a figure of €50 per hour is just as valid, why not even €60 per hour? It’s the same argument as €11.95.
The reason the unions are calling for those figures is not looking out for the interests of low paid workers but rather setting a benchmark to increase their existing members claims without having to increase productivity. The Swiss people recently rejected a high minimum wage in a democratic referendum, why?. Note the change in terminology from “minimum wage” to “living wage” - why is this?
Another fact that is established and not disputable is that such a law guarantees unemployment when the productivity of your labour does not deliver worth to the employer. It has an additional effect that the existing employees must work much harder to justify the payments of said figure and it eliminates people with no or low skills from the labour force bolstering a permanent class of welfare dependants (until the system breaks). In order to maintain the illusion governments then intervene again and subsidise employment through schemes like job-bridge. (they do the same in Sweden and Germany)
As DP points out we are are in a single currency bloc up against Germany and their successful companies have concentrated on raising productivity though capital investment, apprenticeships, better management etc. This is a country with a government that is determined to increase the cost of living in order to increase taxation revenues and devalue the cost of debt through inflation, those are the consequences of taking on excess debt.