This item appears to be a 
vintage crystal salt cellar, likely produced by Daum France. 
Details
  • Material: The item is made of clear, high-quality crystal glass.
  • Design: It features a wavy, organic, or bow-like shape, characteristic of designs from the mid-20th century.
  • Brand: Similar items online are often signed "Daum France" on the bottom.
  • Function: While sometimes mistaken for an ashtray, this specific shape is typically used as a small dish for serving gourmet or specialty salts (salt cellar or salière) or caviar.