"Engelbert Strauss" is a big German company that makes all kinds of functional work wear. Unlike some other companies' websites (etnies!), their website is really well-functioning and is also available in three languages (German, English, and French).
The following safety boots should be vegan (leather-free). Please double-check before you buy. You can search their website for "free of leather" or "lederfrei" (German). Unfortunately, the search for "sans piel" (in French) doesn't seem to work. But if you click on the links below, then change the language at the top of the page to French (FR), and look at the info describing the shoes, click on "plus", you should find the "leather-free" ("Équipement sans cuir") bullet point.
Metallica safety boots - waterproof - from European size 40
"Steel toe cap, steel midsole" "steel cap and puncture-resistant steel sole"