In my research I found that the main triggers were mainly pulled by France and GB:

• GB: Occupation of Egypt without France.
• France: Expansionist policy in Western Africa that threatened the sphere of GB and pushed it towards acquiring land. Also the French acquired land in the Congo area.

However: France didn't make the expansionist policy in Western Africa its official policy before GB occupied Egypt and also ratified the Teke-Brazza treaty (in Congo) afterwards. But there are also a few points that speak against the British fault: They wanted to occupy Egypt with the french, who then backed out in the last minute. Also France had to handle with problems in Tunisia during that time and was thus not unhappy with the occupation of Egypt by GB.

So who's fault was it or is there just no way to answer that? Would the scramble have happened without any of those developments, simply because the emerging powers in Europe (namely Germany and Italy) didn't allow for any power vacuums anymore?