Floor load ratings are given as pounds per square foot (PSF) and is dependent on several factors. To properly answer your question we would need to know the joist size, span, spacing and the area that the safe spreads its load over and what other "live load" objects share the span. We can make some assumptions based on normal design loads for home living areas. Most floors in a living room are designed for minimum loads of 40 PSF live and 10 PSF dead load.
Unless it is built-in, the safe is not part of the structure. It is a live load. If the safe is on a span of 12 feet and is 2 feet in depth it is exerting a load of 700/(12*2)= 29 PSF. The safe easily falls well below live (or dead) load limits designed into modern residential structures, but may limit the number of heavy objects that may share that part of the floor load. The capability of the floor to carry the load is also affected by where on the floor the load is located. Floor load ratings always assume the worst case, that the load is concentrated in the center of the span. If the safe is along a load bearing wall it has very little effect on the floor load.
Anyway for all we know from your post John, you could be on a slab, in which case, none of this would matter anyway.