English version - OPEN ACCESSVersion française disponible ici.This document is intended for all those involved in photonics: entrepreneurs, investors, institutions, researchers, students... For those who see marketing as an illusionist's trick, take some time to read this document! You'll discover that marketing is a tool that anchors products into reality and allows entrepreneurs to quickly become part of the community of users of his or her product. For those who see marketing as a cost, you will understand how marketing is profitable and allows you to avoid dead ends that would cost you hundreds of thousands of euros. And for all entrepreneurs, investors, institutions, researchers or students, curious to understand the methods and tools to generate income and jobs through photonics, you will find some keys to understand the usefulness of our exciting profession and how to practice it.