In short
The Sentinelle Investigations site runs on a WordPress theme built from scratch, with no page builder, with SEO handled in the code: titles, descriptions, canonical addresses and structured markup. It has a pillar page, pages for towns across the Métropole and a tips blog updated every week. Measured on 24 October 2026, it scores 99/100 on mobile in PageSpeed Insights.
Sentinelle Investigations: the client and the starting point
Sentinelle Investigations is a private detective agency based in Lyon. It carries out investigations for individuals, companies and legal professionals. In this trade, trust is won before the first call: visitors want to know who they are dealing with, whether the agency is licensed to operate and how to reach it discreetly.
The starting point was a static HTML and CSS site. The goals for the new site:
- publish advice articles without touching the code;
- get found on searches that name the town;
- show the CNAPS licence at the very top of the home page;
- turn a visit on a phone into a call or a quote request.
A clear structure: one address per topic
The Sentinelle Investigations site is built around a pillar page, "private detective in Lyon", which presents the agency and leads to the rest:
- four investigation areas: individuals, professionals, heir tracing and legal expertise;
- an advice blog sorted into three categories, for individuals, companies and legal questions;
- a menu reduced to seven entries, with a submenu of investigations sorted by audience.
The principle: one page per topic, one address per page. Two pages aiming at the same search compete with each other in Google. When that happened, one was merged into the other, with a permanent redirect so that nothing was lost.
Pages for each town in the Métropole
In this trade, many searches name the town. The site has pillar pages for Lyon, Villeurbanne, Vénissieux, Saint-Priest and Vaulx-en-Velin, completed by pages for other towns in the Métropole, built on a common template.
Town names and their postcodes come from a single list, stored in the theme: a correction is made once and applies everywhere. Towns outside the Métropole de Lyon were deliberately left out.
I apply the same rule to Orbitoile: one useful page for website design in Villeurbanne, rather than one page per district.
SEO handled in the code
Titles, descriptions, canonical addresses, social sharing tags and structured markup (JSON-LD) are produced by the theme itself, from the content of each page. The Rank Math plugin is used for the sitemap and for checking the writing, without rewriting the titles.
The result: a single system decides what Google reads, with no conflict between two plugins, and the markup stays identical from one page to the next. The home page FAQ is marked up too. Google's starter guide covers the basics, on its SEO Starter Guide page.
A home page that reassures and gets people to act
The home page brings together what a worried or hurried visitor wants to see:
- the CNAPS licence and its number, at the top of the page;
- a section of Google reviews left by real clients;
- an accordion FAQ that answers the questions people ask before a first call;
- an assistant with ten pre-written scenarios, with no artificial intelligence or external service;
- the latest blog articles and the manager's columns published on the Journal du Net.
On a phone, the action buttons open a simple choice: call, write an e-mail or fill in the form. The contents lists of long pages are collapsed by default on mobile, to leave room for the text. At the top of the home page, a particle animation adds movement without getting in the way of reading.
Speed, security and publishing
The JavaScript was taken out of the pages and stored in dedicated files. Icons are drawn as inline SVG, instead of loading a full icon library, and images are served in WebP format.
On the security side, the administration login address is customised, login attempts are limited and the site is backed up automatically.
The Sentinelle Investigations articles are prepared in batches and scheduled, at a pace of two per week, with their image and SEO fields already filled in. The agency has nothing to format.
The measured results of the Sentinelle Investigations site
Measurements taken on 24 October 2026 on the home page, with PageSpeed Insights:
| Mobile measurement | Result |
|---|---|
| Performance score | 99/100 |
| Display of the main content | 1.1 s |
| Responsiveness | 102 ms |
| Layout stability | 0,00 |
| Page weight | 279 KB |
The score can vary slightly from one measurement to the next. Google explains what these indicators cover on its Core Web Vitals page. Traffic and contact figures belong to the agency: they are not published here.
What you can take from it for your site
Your business is probably not a detective agency, but the principles carry over:
- one page per topic and one address per page, so you do not compete with yourself;
- local pages only where you have something of your own to say;
- action buttons designed for the phone;
- a light site that displays fast.
These principles hold for a custom-coded site as well as for a well-built WordPress: the WordPress or custom-built site guide helps you choose. To take over an existing site without losing its SEO, see the website redesign page, and to be found near you, the local SEO in Lyon guide.
Key takeaway
The Sentinelle Investigations site combines a simple structure, useful pages for each town, SEO managed in one place and action buttons designed for the phone. It scores 99/100 on mobile, and I keep improving it.