‘La rue est un véritable musée pour tous.’ So wrote writer and artist Hergé, who is most famous for his comic book series The Adventures of Tintin. Translated into English, his aphorism reads: ‘The street is a veritable museum for everyone.’

What did Hergé mean by this? He was talking about people-watching. We go to museums to learn about the past. To learn about people, we can simply stand in a street and be observant.

I spend my summers in the south of France, and one of my favourite aspects of life in this part of the world is the cafe culture. By ‘cafe culture’ I do not mean visiting a chain coffee shop for a quick iced coffee and a cake, surrounded by people gossiping and tapping away on laptops and tablets. I mean the original and most wonderful cafe culture which is an intrinsic part of French life. I am talking about really good coffee, table service and an entirely unhurried pace. I am talking about sitting at a pavement table and having all the time in the world to people-watch – and most likely being surrounded by plenty of other people who are also taking time out not to chat or work, but to sit and breathe and observe.

Any good writer must also be a good observer. ‘Write about what you know’ is a popular adage, but of course we know very little unless we watch and absorb and consider and learn. For my latest novel series, Andalucían Nights, I did plenty of people-watching in Spain. The character of Leandro in Masquerade, in particular, was inspired by a very handsome gypsy man I saw on a beach in Andalucía.

For this series, I did not stop at being inspired by my observations of people, however; I infused into the writing this idea of learning through watching. Each of my heroines is a writer: Alexandra in Indiscretion writes romance novels; Luz in Masquerade writes biographies; Luna in Legacy is a science writer. Thus these women are naturally predisposed to being observers, and wherever they go the street is indeed their museum – they drink in the Spanish culture around them.

But my heroines do not merely passively take in sights they happen across, they seek out scenes that will interest and inspire them, and this is especially important when it comes to the gypsy communities in the books. Each heroine is fascinated by the gypsies, and her curiosity draws her to watch them at their camp, so that with each book there is the sense of history repeating itself.

First, in Indiscretion, Alexandra’s determination to find Salvador leads her right into the gypsy camp. What she finds there shocks her deeply:

It was then that she caught sight of a crowd of gypsies gathered at the wide entrance of one of the caves, a hundred yards away from where she was standing. Unlike the others, this one glowed with flickering light. Alexandra carefully weaved her way through the cluster of people, trying not to draw attention to herself. Several of the gypsies were carrying candles, the ends of which were wrapped in paper, careful not to let the wax drip onto their hands. Salvador stood at the entrance of the cave, his face pale and drawn. Beside him was Esmeralda, stiffly upright, her mouth grave, her beautiful blonde hair partially concealed by a large silk shawl.

Further inside the entrance, men were crouched on the ground, drinking wine from goatskin gourds. One tall, hawk-eyed gitano, a scar deeply etched down the side of his face, was perched on a rock, sharpening a short-bladed knife with a stone, and taking rough swigs of wine. Suddenly, the gypsies got up and started to dance. Their singing was a sort of raucous chant on a monotone, accompanied by castanets, hand-clapping and the rhythmic tapping together of two stones. Then, as the men drew back into the shadows, the women came forward, forming a wild circle around an open coffin. Their sinuous bodies, wrapped in flowing loose dresses, wriggled in the eerie glow of the flames. They were swaying their hips like witches at in incantation, and Alexandra half expected to see black cats appear at any minute, clinging to their backs with raised fur.

Alexandra has stumbled into the funeral of a child, and the gypsies’ customs for this sad event – in particular, the rhythmic ‘bee dance’ – are very unsettling for her. She feels she is ‘in the midst of some hellish nightmare’.

Alexandra does not find affinity with the gypsies, but her daughter certainly does: Luz falls in love with Leandro, the son of a gypsy. Luz comes to the camp in the evening and, hiding behind a large clump of bristling cactus, she watches Leandro play his guitar and sing in the flamenco style for his gypsy family. Luz’s desire to observe and learn has driven her to this place, but she soon becomes uncomfortable, feeling that she is an illicit onlooker.

As he opened his eyes, the gypsy turned towards where Luz was standing. Like deep opal jewels his green irises shone in the semi-darkness and the look of torment in them was harrowing. She made herself smaller. Had he noticed her? The shouts of Olé! and the clapping of hands and stamping of feet were overwhelming, echoing the pounding of her pulse. Men slapped the gypsy singer on the back and young gitanas appeared from every side, screaming, ‘Leandro! Leandro!’ They surrounded him, embracing, hugging and cajoling.

Steel fingers pinched cruelly at Luz’s heart. It was getting colder and the sea wind was beginning to blow, lifting small clouds of dust from the rubble around the encampment. Now lonely, hollow and a little sad, she was not a part of these strange, passionate people, merely an onlooker, an intruder; she had no right to be there. A sudden fear came over her that she might be caught watching them, that he could have seen her, so she turned her back on the scene of merriment. It was time to go home.

In Legacy, the heroine Luna need not feel discomfort over visiting the gypsy camp; she stumbles across it while searching for the ruins of a Moorish mosque, and is guided to the camp by a gypsy lady named Morena. Whereas Alexandra witnessed a gypsy funeral for a child, Luna is afforded the opportunity to watch a ceremony for a newborn baby.

There was a large hollow in the ground next to the cave and a small fire had been lit alongside it. The matron poured water into it and Ruy immersed the child twice in the hole. He then held little Luis over the flame while enunciating a few words in Caló before giving him to his mother.

‘He is bestowing upon him the gift of immortality,’ Morena whispered, ‘an old tradition that some of us follow and that will bring much luck to the child.’

A cradle made of bamboo was brought out. The matron handed Ruy three sprigs of garlic and three pieces of bread, which he placed underneath the mattress. Then, dipping his finger in the hot cinders, he marked the child’s forehead with a semi-circular sign illustrating the moon.

‘The garlic and the bread are for the three goddesses of fate,’ said Morena. ‘El Mèdico has explained to us that this tradition we have comes from the ancient legends of Greece. The first goddess spins the thread of life for each person with her spindle, the second measures it with her rod, and the third determines when and how it should be cut.’

Luna’s initial reaction is akin to Alexandra’s – she is judgmental. She considers the ceremony to be ‘arcane symbolism and superstition’, and assumes that Ruy has not taken proper care of the baby by bathing him in muddy water a hole in the ground. In fact, though, she later discovers, the hole is tiled and the water was clean and warm – she misjudged what she saw.

The common theme in these books is that one must watch and learn about another culture, not make assumptions and judge. For Alexandra, in the prejudice-rife 1950s, this was not easy. But by Luna’s generation, there must be a change. As Luna watches, she must open her mind; she must challenge preconceptions and assumptions. Only then can she respond to the ‘odd stirring’ she feels inside when she sees Ruy with the gypsies – ‘as though some inner part of her was reaching out to it all, like a hungry sapling seeking the sun’.