But now we know just how bad they are, thanks to fresh figures from transport planning app CityMapper.
All photos: AFP
If you've ever commuted to work by Metro or RER in Paris then you're no stranger to delays.
The app has collated data from the month of October based on the number of delays across the period, together with the average number of minutes that each line was affected by these delays.
CityMapper noted that 50 percent of all incidents were registered in peak hours of 6am to 9am and 5pm to 8pm – even though these hours represent just 30 percent of the lines' operating hours.
And coming in at last place – and by a long shot – was the RER E line that serves the city's eastern suburbs.
The line had 20 delays in October, which lasted an average of almost 3.5 hours each time.
However, a huge 18-hour delay on one day was enough to seriously affect its score.
The best running line was Metro Line 1, which is one of the two “driverless” lines, and which links the city's east and west.
It recorded just 12 disruptions with an average delay time of 26 minutes and 35 seconds.
Close behind was line 3, followed by lines 9, 14, and 13.
The worst rated Metro line was number 6, which runs through the southern half of the city, and which had 21 disruptions throughout the month over an average of 2h16mins per delay.
Line 10 and line 5 performed the best in terms of fewest incidents reported, each recording just five throughout October.
The full list for October (from best to worst in average delay time):
Metro Line 1: 26m35 (12 incidents)
Metro Line 3 28m17 (7 incidents)
Metro Line 9 29m11 (11 incidents)
Metro Line 14 36m (5 incidents)
Metro Line 13 38m17 (21 incidents)
Metro Line 4 38m47 (23 incidents)
Metro Line 2 44m51 (14 incidents)
Metro Line 5 52m23 (23 incidents)
Metro Line 12 55m49 (21 incidents)
Metro Line 10 1h07m (5 incidents)
Metro Line 7 1h07m (17 incidents)
Metro Line 8 1h21m (25 incidents)
Metro Line 11 1h47m (10 incidents)
RER D 1h59m (25 incidents)
RER A 2h04m (32 incidents)
RER B 2h09m (33 incidents)
Metro Line 6 2h16m (21 incidents)
RER C 2h17m (27 incidents)
RER E 3h23m (20 incidents)
The five RER commuter lines all finished within the bottom six places (on a list of 19 lines), with D performing the “best” with an average two-hours delay time.
Next best was line A, then B, then C, before E which took last place.
A spokesperson from CityMapper noted that the RER commuter lines were particularly badly hit by delays due to reports of “suspicious packages” reported on board, signaling failures, and technical problems.
Paris transport chiefs at RATP have suggested that the unofficial statistics should be taken with a pinch of salt.
“The only analysis that is relevant is one that has been taken over a long period of time and that has been matched with a detailed analysis of the causes,” it said in a statement.
If being stuck on a Paris Metro is your idea of hell, don't forget you can sometimes walk just as quickly. A version of the Paris Metro map listing walking times between each station went viral last year.
Transport planner Guillaume Martinetti told The Local at the time that he hoped the map would get people out and about more.
Photo: Guillaume Martinetti