It would be interesting to see the percentages for scientists and researchers independently. For France, for instance, researchers' wages are not very high. A lecturer typically starts with about 2115 euros per month before taxes typically for instance. On the contrary, I think that the salary of engineers is competitive with the ones in the UK and Germany.
Indeed this a low wage considering the cost of life, but two third of French earn less than that [0].
A few days ago a statistic about middle class in France was considering 1200 euros as representative of French middle class, even if this is roughly the legal minimum wage.
[0] https://www.inegalites.fr/Salaire-etes-vous-riche-ou-pauvre