It’s talking about tangible cultural assets that can be moved (e.g. paintings, books), and those that can’t (well, not easily), such as buildings.

The Wikipedia page here mentions a bit about it:
https://en.m.wikipedia.org/wiki/Cultural_heritage


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Note added at 22 mins (2018-07-21 09:25:24 GMT)
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Edited to add this as I couldn't copy paste properly on my mobile:

This is the section on the wikipedia page:
Cultural property includes the physical, or "tangible" cultural heritage, such as artworks. These are generally split into two groups of movable and immovable heritage. Immovable heritage includes building so (which themselves may include installed art such as organs, stained glass windows, and frescos), large industrial installations or other historic places and monuments. Moveable heritage includes books, documents, moveable artworks, machines, clothing, and other artifacts, that are considered worthy of preservation for the future. These include objects significant to the archaeology, architecture, science or technology of a specified culture.

For the sake of completeness, note the distinction here is between real objects that can be moved (mueble, e.g. artwork, tools, documents) and can't be moved (inmueble, like a building). It is not talking about the difference between tangible (artwork, books and building) and intangible (songs, dance, recipes), even though you could argue the latter can't be moved physically.

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Note added at 24 mins (2018-07-21 09:27:50 GMT)
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And here's a brief description of the differences from UNESCO:

http://www.unesco.org/new/en/culture/themes/illicit-traffick...