The short answer
Book before you arrive, through your riad or a tour operator, and ask to see the guide's licence badge when you meet. Licensed guides are regulated and vetted; the people who offer to guide you in the street are almost always not. Agree the length of the walk, what it covers and whether shops are included before you set off.
In more detail
A good guide changes a first day in the medina. You skip the wrong turns, the faux guides drift away, and you see the workshops, foundouks and quieter quarters that are hard to find alone. In Fes, where the medina is far larger and GPS often fails, a licensed guide is close to essential.
Spotting a fake guide comes down to who started the conversation. A licensed guide does not need to find clients by falling into step with tourists in the souk. Unofficial guides cluster at the busy medina gates and around Jemaa el-Fna, and they often open with a story: a closed street, a festival, a special day at the tanneries. Their tour tends to end in a carpet or leather shop that pays them a cut of what you spend, and then they ask you for payment too. In Fes the people offering to 'help' near Bab Bou Jeloud are almost always unlicensed.
Say what you want from the day. If you have no interest in shopping, tell the guide at the start; a professional will respect it. If you want to buy a rug, a guide can help you find honest dealers, but you are under no obligation in any shop.
If you would rather walk alone, that is fine. Use an offline map, decline offers of help with a firm, friendly no, and keep moving. Many visitors take a licensed guide for the first morning only, to learn the main lanes, and explore by themselves after that.
You can ask for a guide in a particular language, and you can ask for a female guide. Licensed women guides work in Marrakech and increasingly on Atlas and Ourika trips. A woman guide is good company for any traveller and can take you into spaces a male guide sometimes cannot.
Good to know
- Ask for the guide's name and phone number before the day.
- Meet at your riad or a named landmark, not a random street corner.
- Tip at the end if you are happy with the day.