Accepting cards in store: POS terminals from A to Z. 8 chapters and a final quiz.

Chapter 1. The card-present merchant agreement.

Before you plug in a single terminal, you need a card-present acceptance agreement signed with an acquirer. In France, that role has traditionally fallen to the merchant's bank, and increasingly to a specialized provider. The agreement assigns you a merchant ID and an MCC that describes your business, and it defines which networks you accept. A French bank agreement covers CB, Visa, and Mastercard as one package; American Express, JCB, or Diners require separate agreements with those networks.

The merchant fee (MSC, merchant service charge) is deducted from every transaction. It stacks three layers: interchange, paid to the cardholder's bank; network fees (CB, Visa, and Mastercard scheme fees); and the acquirer's margin. In Europe, Regulation 2015/751 caps interchange at 0.2% for consumer debit cards and 0.3% for consumer credit cards. Depending on the merchant's size and negotiating power, the MSC ranges from about 0.3% for large retailers to more than 1.5%. At subscription-free fintechs, it rises to a flat rate of 1.6% to 2%.

Chapter 2. Choosing a POS terminal: from countertop to smartphone.

The market has broadened considerably. Countertop terminals have been joined by touchscreen Android terminals, mPOS readers paired with a smartphone, and, more recently, SoftPOS, which turns the phone itself into a terminal. The right choice depends on four questions: where you take payments (counter, dining room, on the move), how many transactions a day, with which register, and at what total cost.

Chapter 3. Under the hood: nexo, CB 6.0/FRV6, and CB2A.

An in-store payment runs through a protocol stack that is quite different from e-commerce. At the bottom, the EMV kernels (contact and contactless) communicate with the card. Above them, the acceptance application applies the network rules, which in France are set by the GIE Cartes Bancaires specification (France's domestic card scheme). Around this core sit two exchanges. The register protocol connects the terminal to the POS software; the acquirer protocol carries authorization requests and batch uploads to the bank.

Chapter 4. Installation and the settings that make all the difference.

Two identical terminals can produce very different results depending on how they are configured. Five settings deserve particular attention: MCC, currencies, tipping, pre-authorization, and multi-merchant setup.

• MCC (Merchant Category Code, ISO 18245): 4 digits that describe the business (5812 restaurant, 5411 grocery store, 7011 hotel, 7512 car rental). It determines interchange, pre-authorization and tipping rules, issuers' anti-fraud checks, and even whether certain cards are accepted (corporate cards or gift cards can be restricted by MCC). A wrong MCC costs you in unexplained authorization declines.
• Currencies and DCC: a terminal can offer foreign cardholders the option to pay in their home currency (Dynamic Currency Conversion). The merchant receives a share of the FX margin, but the rate is almost always unfavorable to the customer. Since 2020, EU rules have required the markup over the ECB reference rate to be displayed. Enable it with your eyes open: the cardholder must always be able to choose euros.
• Tipping: on restaurant MCCs, tip mode lets a tip be added before approval or adjusted afterward, depending on the network. Set it up with the acquirer, never by “forcing” a second payment.
• Multi-merchant setup: a single terminal can carry several agreements (two companies, or CB + Amex + digital meal vouchers), with each flow routed to the right account.
• Manual key entry (MOTO): disabled by default on most card-present agreements. Leaving it enabled without a card-not-present agreement is a classic entry point for fraud.

Pre-authorization: the tool for hotels and car rental companies

A pre-authorization reserves an amount against the card's limit without debiting it. It serves as an electronic deposit for hotel (7011) and car rental (7512) MCCs, and it can be extended if the stay runs longer. A completion for the amount actually due then closes it and releases the rest of the hold. Its validity period varies by network and MCC, typically 7 to 31 days; after that, the hold expires and the completion may be declined.

Chapter 5. Contactless: limits and special cases.

Contactless (NFC) has become the default way to pay in store. About six in ten CB card payments in stores in France are contactless. The per-transaction limit for a physical card has been €50 since May 11, 2020 (up from €30, raised at the height of the COVID-19 crisis). Above that, the terminal requires the card to be inserted and the PIN entered.

On the risk side, contactless remains one of the safest channels. Year after year, the Observatoire de la sécurité des moyens de paiement, run by the Banque de France (France's central bank), reports a fraud rate for in-person payments far below that for remote payments. Contactless use of a stolen card is capped by design by the €50 limit and the chip's counters. For a merchant taking card-present payments with PIN or CDCVM, liability for fraud chargebacks in principle falls on the issuer, not the merchant.

Chapter 6. Batch uploads, deposits, receipts, and data.

In store, authorization is instant, but the money moves later. During the day, the terminal stores authorized transactions and sends them to the acquirer as a batch overnight. This end-of-day batch upload makes up the deposit. The merchant's account is usually credited on D+1 (next business day), with fees either deducted or billed separately depending on the agreement.

Receipts: what gets printed, what to keep

• Two separate receipts: the cardholder receipt (PAN masked, only the last 4 digits shown, a PCI DSS requirement) and the merchant receipt, which serves as proof of the transaction.
• Since August 1, 2023 (the AGEC law, France's anti-waste law), printing register receipts and card receipts is no longer automatic in France: they are provided on request or sent electronically. Exceptions: canceled transactions, certain amounts, and warranties.
• Keep merchant records (receipts or the terminal's electronic journal) for at least 13 months: that is the cardholder dispute window, and your evidence for a retrieval request or a chargeback.
• The transaction log in the terminal or the acquirer portal is the source of truth for reconciliation. Exporting it regularly means you do not depend on the terminal's memory.

Chapter 7. Outages and fallback mode: keeping payments going.

A terminal that goes down on a Saturday afternoon costs you sales directly. The fix has two parts: fast troubleshooting for common faults, and fallback options prepared in advance.

• Check the network first: an unplugged router or Ethernet cable, or no Wi-Fi or 4G, explains the vast majority of “broken terminals.” Restarting the terminal and the router fixes many cases.
• Check the basics: paper (a terminal with no roll may refuse to take payments), the portable terminal's battery, an interrupted overnight update.
• Switch connections: most recent terminals can switch from IP to 4G (or vice versa) in the settings menu.
• Call the maintenance provider: a bank rental agreement usually includes hardware replacement within 24 to 48 hours; if you bought the terminal outright, check what your warranty covers.
• Activate plan B: a second terminal, a backup mPOS in the drawer, or SoftPOS preinstalled on the manager's smartphone. These three low-cost options can save a day's sales.

That leaves fallback mode in the strict sense: the terminal works but cannot reach the authorization server. Depending on the CB settings, small transactions can go through offline, within strict floor limits, and are regularized at the next batch upload. For larger amounts, the last resort is a phone authorization request to the acquirer's authorization center, where an operator provides an authorization number to key into the terminal.

Chapter 8. The total cost of a POS terminal.

Comparing offers requires a total cost of ownership view: hardware, subscriptions, commissions, and ancillary fees. Here are typical figures seen on the French market in 2025–2026.

The classic trade-off pits the bank model (rental + negotiated commission, often with a monthly minimum) against the fintech model (hardware bought outright, no subscription, higher flat commission). The break-even point is usually around €2,000 to €2,500 in monthly card sales. Below that, the fintech flat rate wins. Above it, a commission negotiated with a bank quickly becomes cheaper, as long as you negotiate hard.