Very Specific Paris Metro Map Question

1) The dotted lines mean there is an underground walkway from one station to another. Solferino station has an exit that leads to the museum via an underground walkway.

2) I edited my answer to your 2nd question. I know see what you mean. But as others already explained, the answer about the rectangles can be found on the map itself https://parisbytrain.com/wp-content/uploads/2024/06/paris-metro-map-2024-a.pdf

On the official RATP.fr map there is a key in the upper left corner that answers your questions: https://www.ratp.fr/sites/default/files/plans-lignes/Plans-essentiels/Plan-Metro.1736413859.pdf

Dotted lines = liaison urbaine = urban connection = walking I believe (our locals will chime in if that is incorrect)
Rectangle = Pôle d’échange multimodal, métro, RER, tramway = multimodal interchange hub

1. The dotted lines mean there is an underground connection between the 2 stations. On the spider map it may not look like they are close but in real life they are connected by corridors. So....the Musee d'Orsay RER C station is connected with Line 12 Metro by an underground corridor...but seriously I'd walk above ground in this neighborhood as it's quite nice!

2. The thin surrounding rectangle also means you can change from line to line underground. I have not done the Abbesses to funicular transit so am not sure what that is about as the funicular is above ground. That area also shows you can go from the Anvers Metro stop to the funicular. BUT not from Abbesses to Anvers. It must have something to do with it being on the same ticket? Someone here will know for sure.

editing to add: Crossposting with Dutch Traveler and CL. @Dutch Traveler, the rectangle is there on the map you linked. Look at Abbesses to funicular area.

For item No.2, These are connections between the Tram and the Metro at the stops Porte de Charenton and Porte Doree. The Tram station is on the street and there is a stairway nearby down to the No 8 Metro station.

Thank you folks! Question 3: What about Champs de Mars/Bir Hakeim? White dots indicate transfer stations, but these are, at least on the map, distant from each other.

You see the same type of white transfer marks al over Gare Saint-Lazare.

May I suggest you take a look at the versions of the metro maps shared by CL or by me? The meaning of all the different symbols is explained on these maps. This includes the various symbols that can indicate a transfer

Check out https://pariswayout.com. This web site has detailed information about where the entrances and exits are at each station, which will help you immensely in planning your trip. It is an indispensable resource for visitors using the Paris Metro.

The other thing to remember is that signage in the stations refers to the end station at each end of the line. For example, if you're on Line 13, you are either heading for Châtillon / Asnières-Gennevilliers OR St-Denis University. It's a good idea to know this so you can get on the correct platform for the direction you're heading when you get to your station.

In addition to looking at one of the maps that have the key printed on them, consider putting the City Mapper app on your phone (or you use it on your desktop now). It gives excellent instructions to navigate the metro (including walking time), and advises the appropriate entrance/exits (there can be many).

You see the same type of white transfer marks al over Gare Saint-Lazare

These indicate underground passageways, and the area between St Lazare and Opera is a veritable warren. So the connection between Champs de Mars and Bir-Hakeim is also one. Champ de Mars is an underground RER station and Bir-Hakeim is an elevated station, so I presume there is an underground passageway with an elevator up the the Bir-Hakeim platform.

The dotted lines mean there is an underground connection between the 2 stations

I am not sure this is the case, as if it was, then it would be shown as a double line with white interior, much like as is shown for the nearby St Michel-St Michel Notre Dame-Cluny La Sorbonne Metro connecting stations. It is listed as a "Laisons Urbaines", which I interpret as a connection where you exit one station, walk above ground, and your Metro ticket will open the turnstile without charging an additional fare (if done in a timely manner).

Question 3: What about Champs de Mars/Bir Hakeim? White dots indicate
transfer stations, but these are, at least on the map, distant from
each other.

Are you basing this on the distance of the two stations on the metro map? The map is a diagram and is not a fully accurate representation of geographical reality. Champs de Mars and Bir Hakeim stations are at most several hundred meters apart and are in fact connected by a corridor, which is why they are connected on the map.

You can't deduce that the two stations are "distant from each other" based on the literal physical distance between two dots, which in this case is likely due to the graphical demands of the two crossing lines.

Just to clarify, the Metro - Tram transfers are at Porte Dorée and Porte de Charenton. No tram anywhere near Dugommier.

The dotted lines mean there is an underground connection between the 2 stations

There is also a similar connection shown between the Gare de Lyon and the Gare d'Austerlitz. That is definitely above ground over a bridge over the Seine as there is no such walkway tunnel under the river.