Same-sex marriage in Paris?

There are several aspects of the rules around marriage in France that would make your plan difficult. As far as I know, it's not forbidden to marry as a non-resident but the law is clearly not intended to make it easy.

• You need to complete some formalities beforehand (publication des bans). It should happen at least 10 days before the wedding but you also need to allow some time for the municipality to process the paperwork and find a slot for you, so realistically we are talking about weeks rather than days.
• By law, the marriage should be celebrated at the town hall. There are a number of exceptions defined in the law (e.g. if one of the future spouses is dying or too sick to move) but the town is not allowed to let you marry anywhere else without a good reason (and even then they have to inform the procureur, who is a bit like a state's attorney/chief prosecutor).
• You need to have a “link” with the municipality. Usually, this means the place of residence of one of the spouses but some family or property can also be deemed enough so with the right connections you might be able to go around this requirement (in practice it's up to the mayor). But you can't just pick a town and get married there.
• Depending on their citizenship, there are additional requirements for foreigners, typically some document from your country of origin certifying that you are able to marry and a certificat de coutume (an affidavit of law explaining the rules pertaining to marriage in your country).

For some time, there were also additional restrictions on same-sex marriages based on international agreements so that citizens of a bunch countries could not enter a same-sex marriage in France but recent court cases should have lifted this restriction. It was in particular the case for citizens of Algeria, Bosnia-Herzegovina, Cambodia, Kosovo, Laos, Morocco, Montenegro, Poland, Serbia, Slovenia, and Tunisia.

One simple solution is to have the legal marriage somewhere convenient, e.g. a registry office in your own country, and have the celebration in a place of your choice.

This is very common. I did it and so did my brother. Our legal marriages and our celebrations, with champagne, guests etc, were on different days in different countries.

It is also common for people whose religion is not the official state religion. Their celebrant might not be able to legally marry them so a separate legal procedure is required.

Same-sex or no, marrying under the tower will be difficult. Most of the answers focused on the practicality of marrying in Paris as a foreigner.

While that may be possible (especially as EU citizens), the ceremony would take place in some government office - the official won't come to the Eiffel tower with you.

However what you can do is to have the legal marriage in your home country or some place where it is convenient for you.

You could then come to Paris and have some form of ceremony under or near the Eiffel tower. I even found a website that offers "vow ceremonies" close to the Eiffel tower as a service - obviously those are not legal marriages, but are as close as you get.

You could also just bring someone you know (minister, friend, relative) to "officiate" the vows and roll your own ceremony.

Note that it has been pointed out in the comments that any religious marriage rites need to be performed after the civil union and any French priest/minister/imam/rabbi will supposedly check your marriage records.

A generic "vow" ceremony without any official religious and legal meaning - like the ones you find on the web - will probably fine regardless.

Note that even those "vow ceremonies" seem to take place somewhere near the Eiffel tower - the area under the tower is now cordoned off as an anti-terrorist measure and only accessible with a ticket; the place will usually be crowded with tourists and may not be the best spot to hold a ceremony with guests.

You can still have the ceremony close to the tower and then go for a visit, though. Or, if it's just the two of you you can just go and say the vows to each other.

France has legalized same-sex marriage since 2013. But I think the main issue here is that you don't live in France.

If you want to get married here in France (with legal and official records) you will need to have a long stay visa and stayed at least 3 months to get married in the Town Hall.

But, if you plan to travel to Paris, there's always an option to get a symbolic wedding with officiant where you exchange your vows. But this is purely symbolic!