I've seen a "préavis de grève" for public transport workers mentioning a length of 3 hours 59 minutes, which will impact travelers and commuters inside and near Paris.
Why does it have that specific length?
Should I expect everything to return to normal after the said 3 hours 59 minutes?
Or is it just some sort of loophole in the law, which means that in practice the industrial action will last for the entire afternoon (since this industrial action is scheduled to take place during the afternoon)?