Find all the real numbers $x$ that verify the equation: $$x-3\{x\}-\{3\{x\}\}=0$$
$\{a\}$ represents the fractional part of $a$
Given the equation:
\[ x - 3\{x\} - \{3\{x\}\} = 0 \]
where \(\{a\}\) represents the fractional part of \(a\).

Let \(x = n + y\) where \(n \in \mathbb{Z}\) and \(y \in [0, 1)\). Then \(\{x\} = y\) and the equation becomes:
\[ n + y - 3y - \{3y\} = 0 \]
Simplifying, we get:
\[ n - 2y - \{3y\} = 0 \]
Thus:
\[ n = 2y + \{3y\} \]

We need to consider different values of \(n\) and solve for \(y\).

1. **Case \(n = 0\):**
   \[ 0 = 2y + \{3y\} \]
   Since \(y \in [0, 1)\), \(\{3y\} = 3y\) because \(3y < 3\). Thus:
   \[ 0 = 2y + 3y \]
   \[ 0 = 5y \]
   \[ y = 0 \]
   Therefore, \(x = n + y = 0 + 0 = 0\).

2. **Case \(n = 1\):**
   \[ 1 = 2y + \{3y\} \]
   Since \(y \in [0, 1)\), \(\{3y\} = 3y - \lfloor 3y \rfloor\). We need \(1 - 2y \in [0, 1)\), which implies:
   \[ 0 \leq 1 - 2y < 1 \]
   \[ 0 < y \leq \frac{1}{2} \]
   Also, \(\lfloor 3y \rfloor = 3y - \{3y\} = 5y - 1\) must be an integer. Thus:
   \[ 5y - 1 \in \mathbb{Z} \]
   \[ y = \frac{m}{5} \]
   where \(m\) is an integer. Given \(0 < y \leq \frac{1}{2}\), \(m\) can be 1 or 2. Thus:
   \[ y = \frac{1}{5} \text{ or } y = \frac{2}{5} \]
   Therefore, \(x = n + y = 1 + \frac{1}{5} = \frac{6}{5}\) or \(x = 1 + \frac{2}{5} = \frac{7}{5}\).

3. **Case \(n = 2\):**
   \[ 2 = 2y + \{3y\} \]
   Since \(y \in [0, 1)\), \(\{3y\} = 3y - \lfloor 3y \rfloor\). We need \(2 - 2y \in [0, 1)\), which implies:
   \[ 1 < y < 1 \]
   \[ \frac{1}{2} < y < 1 \]
   Also, \(\lfloor 3y \rfloor = 3y - \{3y\} = 5y - 2\) must be an integer. Thus:
   \[ 5y - 2 \in \mathbb{Z} \]
   \[ y = \frac{m}{5} \]
   where \(m\) is an integer. Given \(\frac{1}{2} < y < 1\), \(m\) can be 3 or 4. Thus:
   \[ y = \frac{3}{5} \text{ or } y = \frac{4}{5} \]
   Therefore, \(x = n + y = 2 + \frac{3}{5} = \frac{13}{5}\) or \(x = 2 + \frac{4}{5} = \frac{14}{5}\).

Hence, the solutions are:
\[ \boxed{x \in \left\{0, \frac{6}{5}, \frac{7}{5}, \frac{13}{5}, \frac{14}{5}\right\}} \]