Who was the Treaty of Versailles directed at?
The best way to answer this is to say that the Treaty of Versailles was directed at Germany. A treaty is binding on all nations that sign it, but this treaty was clearly "directed at" Germany.
The treaty was directed at Germany because Germany was the leading country on the losing side of the war. The allies (particularly France and the United Kingdom) felt that Germany would continue to be a danger to world peace unless something was done to keep German power down. The Treaty of Versailles was largely aimed at doing this. For this reason, it took away large chunks of German territory. It also severely limited the size and nature of Germany's military. By doing these things, it was meant to ensure that Germany could not be a threat to world peace.
In these ways, the treaty was clearly "directed at" Germany.