Some of you may have seen this question below, elsewhere on the internet. Judging from comments, it appears there is no consensus at all (online) over who has (first) priority, and who then has subsequent priority…Personally I think C has the first priority, but after that..?
I should add that the majority of comments favoured C, under priorité à droite rules (no markings on the road etc)
I’d have thought that A had priority as it is proceeding ahead and not turning across the paths of other motorists.
But a rule of safe driving is to give priority, not take it. I would expect the better drivers to make it clear to the others that they were ceding priority
I thought A has priority because they are continuing in a straight line and not crossing to turn another. I like the American way whereby whoever got to there first has right of way over others, very civilised!
I just don’t understand why the French can’t be arsed to mark every intersection. They spend how much money on ‘yellow diamond’ signs, ‘yellow diamond’ signs with lines going through them’ and others- why not just spend the money on more STOP signs? And yes, I suppose they can’t mark every cow crossing, but surely everything in a city the size of mine-Cholet- should be marked. When I bought my car in town I was almost pronged at the first intersection and it would have been my fault.
It’s an AI - created image, isn’t it, so an unrealistic situation has been created?
If it’s Paris, as I infer from the colonne Morris you can see, then certainly priorité à droite probably applies.
It’s not unrealistic for 3 cars to approach an unmarked intersection..and then chaos…until we sort out who are the Alpha males.
It’s the one in the white Tesla then
But, seriously, the problem has deliberately been created using AI, so - from people’s responses - there is no generally accepted correct solution.
In reality, such a junction would have been marked long ago, because of the number of collisions that would have occurred.
Well B’s not going anywhere because A has not left him or her enough room to turn into that smaller road, so it’s A or C. 
Priorité à droite then kicks in so yes C should go first.
But I agree that a few road markings would help a lot!
PAD is a silly rule, it would be better if France adopted the UK policy where the traffic on the larger of the roads has right of way.
All that said, I agree with @_Brian that the safest thing for all concerned is to negotiate between them, though easier said than done sometimes.
I like the policy adopted by Tony the former Uber driver who runs the London DashCam channel on YouTube - always be on the look out for idiots and put your ego aside if you can tell they are about to do something stupid like overtake on the inside or cut across you to make a turn.
Not sure I agree - sounds like a recipe for disaster! I also think the US thing of “turning right on red is OK except when it’s not” is bloody daft!
B can’t go anywhere because A has taken up the carriageway.
Oh, this has made me chuckle..
According to the picture in the opening post… A is coming out of a road which isn’t actually wide enough for 2 cars to pass… so B can’t get in there until A has got out! 
Here’s the official thingy for crossroads without panels/signals:
“give way to the right” and " courtesy" are the major players 
As agreed, B’s not going anywhere until A moves. So B waits.
Priorite a droite does NOT apply where C is concerned in relation to A because C is coming from the left side of A.
Therefore A goes first, then C, then B.
Simples.
Occasionally, we’ve found ourselves in a similar situation and each driver has hesitated, thankfully, and slowly moved, rather than charging on regardless…
Courtesy at all times has helped keep us alive
(my pet hate is someone who drives at top speed through a Stop sign … we’ve had a number of near misses from such stupid fools.) 
In my view, the alpha drivers are the ones who create safety rather than chaos.
It takes 45 minutes to fill out the insurance accident form so everyone can go first and I’ll just wait 
In Paris, the BMW with the most Go Faster bits added always has priority.
Can you always tell which is the larger road from the driver’s seat? PAD isn’t that bad as an absolute tie breaker when all else fails. But the number of totally unmarked intersections should be close to zero. How much does a STOP sign cost? 20 euros?
Except for the bikers coming from the right, when you are expecting all traffic from the left.
None of those have priority. A must give way to B, B must give way to C and C must give way to A. Thus it requires someone to actively signal priority to one of them who does not have it.
As stated, commonsense and politesse are required and imo B is the one who is better placed to start the process by allowing A to proceed which then gives C the chance to turn safely left followed by B doing likewise.
slight thread drift… but all traffic signs etc have to be a certain standard of construction and fitted to certain specs… I can assure you each costs a lot more than 20€
Indeed as there is no room for B down that carriageway.
