I like the mid-century modern aesthetic.  
If I am doing the conversion correctly, that is .0625 cubic meters.  That would be 26.67 board feet (423.78 bdft/m^3).  8/4 Black walnut goes for around $12.50/bdft around me so that would be $333(~€ 313).  Again, if I am doing the conversions correctly.   
 
    
     --Nathan, TX.  Hire the lazy man. He may not do as much work but that's because he will find a better way.