In French, you'd say "je fais 1 mètre 80" (literally "I'm 1 meter 80") and write it 1m80. Saying "180 centimètres" would be weird in a casual conversation, but fine in a professionnal setting. For a weight of 1500g, you'd usually say "1 kilo 5", maybe "1 kilo 500", but rarely "1 kilo 500 grammes".

So yeah, decimals are so used that you don't even need to tell the unit, it's implicit. I once had an american argue with me about Fahrenheit vs Celsius, because "Fahrenheit is more precise". I guess he was either a superhuman who can feel the difference between 20°C and 21°C, or someone who never heard about decimals.