Referring back to the priorite a droit, I think it’s been mentioned before with respect to junctions out of town, whether or not marked with those fetching green bollards, which may also affect permitted speed?
I don't know about green bollards, but the presence or absence of the priority diamond should be noted.
Those efforts that adorn slip-road junctions? They only affect your speed if you run into them.
They don't affect your speed much unless you stop to remove the debris; I think they're mainly plastic (not that I have hit one to find out)
The famous diamond that is crossed when you enter an agglomeration is a thing of nationales (trunk roads) and is becoming less common as the trunk roads are diverted round towns, made into dual-carriageways or replaced by urban motorways. I hope QG is not planning on seeing too many of them (although she might come across them depending on her route planning, with bypassed nationales sometimes being a good option).
The sign for a priorité à droit is a red bordered triangle with an X in it. They are not always present! The equivalent for where the road has the priority carries a cross, oriented vertical, with a thicker bar vertical (which might be an arrow, can't remember). Self explanatory when you see it; again not always present.
A lot of p à d are being phased out to be replaced by stops. This can give rise to confusion (in places like the Dordogne, which had a lot of p à d) when you cross the old boy wjth a casquette who has done the same junction that way for the last half century and has had a bit of blanc with his petit noir (as he also has done for the last half century). No point in arguing; just look abashed, blow him a kiss and pass on your way. Morale of the story: treat any junction without a visible line or sign with extreme caution even if you think you have the right of way. Even with a line the usual rules of precaution and self survival apply.
Reminder: you are supposed to "mark" a stop by stopping forward movement and putting a foot on the ground; non-respect is a finable offence but no-one (or very few) respect this which is why the FFCT is having constant road safety campaigns on the subject. Amendes are reduced for quick payment for motorists but this is not the case for cyclists; 135€ is just that, not 90€ if paid in 14 days. The world is very unfair - but then a lot less cyclists get fined for "infractions" although we're certainly not saints! (This may have changed but I do not think so. I haven't seen anything to that effect)
Edit: Priorité à droit in towns will not (at least in my experience) have a sign by the junction to warn you. The absence of a white line across the road junction (solid or otherwise) indicates priorité à droit. It's like the speed limit being indicated by the town sign, you are expected to spot this and recognise it for what it is. When in doubt proceed with caution! Some towns do have an indication at the town entry to warn you of blanket priorité à droit. From memory Salbris (in the Sologne ) has one. I have been saved from certain doom on occasion by the car in front respecting the priority when I had completely forgotten!