[This post is written in English but is given from the perspective of someone living in France. The situation in other countries may differ.]

I'm writing about an unusual topic: the choice to use cash (rather than payment cards) when paying at businesses. Over the last few years, essentially since COVID, more and more businesses seem surprised when I pay with cash -- I feel a kind of social pressure not to use it. Hence this post: I will explain why it's legally allowed to pay with cash, why I do it, and why I sometimes don't.

The law

Are businesses required to accept cash payments? in France, the answer is yes, with some exceptions:

• They can refuse coins or bills in bad condition, or money suspected of being counterfeit
• They can refuse payments with too many coins
• They can refuse payment if you don't have change (but I guess this is only if the customer doesn't have the exact amount)
• In some loosely defined cases, cash can be refused when it's inconvenient (e.g., some vending machines, etc.)
• There is a limit to how much you can pay using cash (the maximal amount depends on the type of purchase)

In practice, this law still seems to be respected: I have not seen many places who refuse cash payments outright. However, I see more and more places that don't have change, or complain and ask whether I couldn't use a payment card instead.

The reasons

Here are the main reasons why I think it's important to be able to pay using cash:

• It avoids giving money to payment card companies. On card payments, a percentage of the money goes to the payment card company (instead of the seller). Of course, these companies¹ are an oligopoly: they are hard to compete against because of the network effect. In other words: essentially all customers have a card from one of the major payment networks, so essentially all shops have to accept these networks, and starting a new payment network is complicated because you need both shops and customers to coordinate. By paying in cash rather than card, I make sure that the entire payment goes to the seller rather than payment card companies. I think this is usually a better way to allocate my money.
  • Some shops give discounts to customers who pay cash (because they get 100% of the payment amount). However, in my experience the practice is pretty rare. I assumed that it was because merchants were forbidden to do it because of the contracts that they sign with payment card companies, but this does not seem to be the case, at least with Mastercard or Visa².
  • I am aware that handling cash isn't entirely free -- many businesses pay third parties to handle their cash for them. There is one big difference however: as opposed to payment cards, I am more confident that this is a market with fair competition. Indeed, businesses can switch to a different provider when they want, and their customers will not notice.
• When I pay cash, it does not leave a trace³. This means my bank knows less about how I spend my money -- and indeed, this is none of their business. It's also not the business of merchants to know the history of my payments with them, as some sellers seem to be tracking customers using their payment means. It's also none of the business of the many third parties to which I imagine banks and shops are reselling the payment habits of their customers.
• Cash is more resilient. This makes sense both at an individual level and at a social level. At an individual level, if your bank decides that it no longer wants to do business with you for some opaque reason, or if a technical problem means that your card no longer works, then you can be in trouble. At a social level, cash works better whenever there's a crisis: this was demonstrated, e.g., during the 2025 Iberian Peninsula blackout.
• Many people don't have cards. It's important that these people can also pay and receive payments without needing cards or bank accounts.

The Cash Matters initiative lists many other reasons, more or less convincing, to prefer cash.

The counter-reasons

There are some reasons that sometimes make me reconsider the choice to pay cash:

• For some consumer goods that you buy in-person and which can be returned, some shops will refund you in money when you pay by card, but when you pay cash they will only refund you with a voucher that can only be used in the same shop (and often has an expiration date). For obvious reasons, actual money is better than a store voucher, so I will often compromise and use payment cards for purchases where I might change my mind later.
• Of course, sometimes paying cash is inconvenient, e.g., when I am in a hurry, or when I forgot to stop by an ATM.
• Online payments obviously don't work with cash.
• For some purchases (e.g., related to travel), some payment cards provide some built-in insurance but only if the payment is made with the card. (Of course, such payments are usually made online anyway, so the previous point applies.)
• Some banks offer cashbacks when you pay by payment card. However, for now the amounts have been too small for me to care. Some other banks charge you for ATM withdrawals, but mine does not.

There are other systematic reasons to prefer card payments, but I don't find all of them convincing:

• Cash may make some crime easier. This can happen at an individual level, i.e., you can fall prey to crime (e.g., theft, extortion). It can also happen at a social level, e.g., by making organized crime easier⁴. That said, I tend to find the erosion of personal freedom much more concerning -- I'm more afraid of states and big corporations than I am afraid of criminals.
• Hygiene -- this was a big concern with COVID. However, again, I find it hard to be concerned (see previous point).
• As a computer scientist, I agree that it's unpleasant that cash relies on the difficulty of replicating a physical artefact. Protections against counterfeit money feel a lot like security through obscurity. Still, somehow, it mostly works. You could have expected that the Internet would make it easier for counterfeiters to exchange restricted information, but in reality the opposite seems to be happening: counterfeit euro notes are at a historic low.
  • I understand the intellectual appeal of replacing cash by a digital solution that addresses the current shortcomings of payment cards -- probably involving some form of cryptocurrency with zero-knowledge proofs or something of the sort. Yet, at present, I find it hard to be enthusiastic about cryptocurrencies: I'm disgusted by their huge environmental cost, and the amount of speculation they attract, in comparison with the actual services that they provide. (And yes, I am aware of systems like proof of stake to reduce the environmental impact of cryptocurrencies, but all of this seems pretty far away in the future -- whereas the question of whether to use cash or card payments is a very immediate one.)
• Environmental impact. Measured in terms of greenhouse gas emissions, it seems that paying in cash may have more impact than paying by card. That said, the amounts seem pretty negligible (see, e.g., here): at a few grams per transaction, this is probably very small compared to the environmental impact of whatever you are buying.

Conclusion

Unlike other political issues, I don't see many people around me who care about cash payments -- which is what gave me the impression that this post may be worth writing. To summarize, the cash ecosystem looks like something that would be almost impossible to reinvent today if it didn't already exist. It is a simple but effective way to anonymize transactions and ensure that payments aren't taken over by payment card companies, so I hope it lasts.

I don't know if the right to use cash is seriously endangered in the short term, at least in the EU: the European Central Bank says pretty clearly that they want to keep cash around⁵. However, from what I can see around me in the past years, I'm getting a bit worried that it may become more and more difficult to pay with cash in practice. The move towards a cashless society also seems to be pretty advanced in some countries such as Sweden (see also this critical article from the BBC).

I leave you with some related work, as I searched for other groups who might be advocating for cash payments or investigating the matter. The answer seems to be that such groups exist:

• There is the Cash matters initiative that I already mentioned above.
• There is a KEEP CASH campaign in the UK, which unfortunately seems to be only organized as a Facebook page.
• The US-based ACLU has a piece about cash.
• The US also has a proposed bill to enshrine the right for customers to pay by cash, but I don't know whether it stands a chance of being adopted.
• There is a comparison of the right to pay by cash in EU countries here.

Thanks to Marc Jeanmougin for feedback on this post.

I tend to write a lot about my opinions about academia in my area (theoretical computer science), e.g., about open access, about general problems with academia, etc. If you are interested in this topic, I just contributed an interview to the latest Bulletin of the EATCS, the European scholarly association for theoretical computer science (of which I am now a vice-president).

You can read the interview in PDF format here.