plugs in France

As long as it is for low power, non grounded, devices (cell phone, camera battery, Apple laptops or tablets, etc) the RS adaptors you purchased last year work anywhere and everywhere in Europe. I have used them in every European country without issues.

The UK of course has its own different ones.

Thanks for confirming. I have purchased UK ones separately last week.

By European codes, those two pin "Europlug adapters" cannot be used for appliances drawing more than 2½ amps (575W at 230V), so they are not legal for high wattage appliances like hair dryers. They also do not preserve polarity, so they should not be used for polarized devices (one blade of plug wider). Except for Switzerland, there is no such thing as polarity in European electrical supply systems. Safety that, in the US, is provided by polarized power, is provided by other means in continental Europe.

Are these 2-pin plugs (for 2-pin appliances) , or 3-pin plugs (for 3-pin appliances)?

2-pin is the same for most of Europe (except for UK+Ireland).
For 3-pin, Italy is different to France, they put the 3rd earth pin in a different place.

Except for Switzerland, there is no such thing as polarity in European electrical supply systems.

France and the UK (and anybody else who uses the French or UK systems) also have polarised 3-pin plugs. As most do not, nobody makes any appliances for the European market which rely on polarity, as you could only sell them in some countries.

i need these to mainly charge phones/batteries etc.

i need these to mainly charge phones/batteries etc.

You should be fine. USB voltage converters (that's really what they are - 230VAC to 5VDC) are "double insulated" (square-in-square symbol) and don't need a ground.

As I understand it, there are duplex receptacles sold in France in which the polarity of the two receptacles is opposite (i.e., the right pin socket on the LH receptacle is physically connected to the left pin socket on the RH receptacle.

You are right, the offset grounding pin of the French Schuko receptacle could lend itself to polarization, but no attempt has been made with the conductors of the power supply to assure it.

UK plugs are polarized. There are no 2-blade adapters in the UK; the grounding pin is required to open the blade sockets (although some plugs have non-conductive "grounding" pins, and thus are not grounding.

The plugs you bought to use with your devices in Italy will also work with those same devices in France, yes.