Death on the Marais is the first in Adrian Magson’s Inspector Lucas Rocco series. It’s free (!!!) right now at Kindle US, but not anywhere else (yet) that I could find. I’ve read and liked the first few Rocco titles, including this one. (I’m a little bit biased since I really like France and most things French, but I still think others would like this series…and it has 4.6 stars at Amazon and 3.99 at GoodReads.)
Free at Kindle US
Free now in the UK as well: https://www.amazon.co.uk/dp/B08JCZ4SRY
All seven books in Magson’s Rocco series are £0.99 each, except for the second, which is £1.99. Several of these are new price drops, but some, like the first, are long-term-ish prices. The titles are: Death on the Marais, Death on the Rive Nord, Death on the Pont Noir, Death at the Clos du Lac, Rocco and the Nightingale, Rocco and the Price of Lies, and Death at the Old Asylum. Here’s a link to the series webpage: https://www.amazon.co.uk/dp/B09GF6GRQZ?binding=kindle_edition
And, if you prefer to shop in the US, the first two are $0.99 each and the remainder are $2.99 each, except for the sixth one, which is $3.99 right now. But still not too bad on the pricing. And here’s the link for the series webpage in the US: https://www.amazon.com/dp/B09GF6GRQZ?binding=kindle_edition
And finally, the novella, Rocco and the Snow Angel, is £1.99/$2.99 in the US/UK, although that seems a bit expensive to me for 58 pages…
Kindle US: https://www.amazon.com/dp/B08P4BJ7W6
Kindle UK: https://www.amazon.co.uk/dp/B08P4BJ7W6