diff --git a/__tests__/rpcProvider.test.ts b/__tests__/rpcProvider.test.ts
index a10bdcabf..c8bf0615e 100644
--- a/__tests__/rpcProvider.test.ts
+++ b/__tests__/rpcProvider.test.ts
@@ -18,6 +18,8 @@ import { StarknetChainId } from '../src/constants';
 import { felt, uint256 } from '../src/utils/calldata/cairo';
 import { toHexString } from '../src/utils/num';
 import {
+  compiledC1v2,
+  compiledC1v2Casm,
   compiledErc20Echo,
   compiledL1L2,
   compiledOpenZeppelinAccount,
@@ -109,24 +111,47 @@ describeIfRpc('RPCProvider', () => {
   });
 
   describe('Test Estimate message fee', () => {
-    const L1_ADDRESS = '0x8359E4B0152ed5A731162D3c7B0D8D56edB165A0';
-    let l1l2ContractAddress: string;
+    let l1l2ContractCairo0Address: string;
+    let l1l2ContractCairo1Address: string;
 
     beforeAll(async () => {
       const { deploy } = await account.declareAndDeploy({
         contract: compiledL1L2,
       });
-      l1l2ContractAddress = deploy.contract_address;
+      l1l2ContractCairo0Address = deploy.contract_address;
+      const { deploy: deploy2 } = await account.declareAndDeploy({
+        contract: compiledC1v2,
+        casm: compiledC1v2Casm,
+      });
+      l1l2ContractCairo1Address = deploy2.contract_address;
     });
 
-    test('estimate message fee', async () => {
-      const estimation = await rpcProvider.estimateMessageFee({
+    test('estimate message fee Cairo 0', async () => {
+      const L1_ADDRESS = '0x8359E4B0152ed5A731162D3c7B0D8D56edB165A0';
+      const estimationCairo0 = await rpcProvider.estimateMessageFee({
         from_address: L1_ADDRESS,
-        to_address: l1l2ContractAddress,
+        to_address: l1l2ContractCairo0Address,
         entry_point_selector: 'deposit',
         payload: ['556', '123'],
       });
-      expect(estimation).toEqual(
+      expect(estimationCairo0).toEqual(
+        expect.objectContaining({
+          gas_consumed: expect.anything(),
+          gas_price: expect.anything(),
+          overall_fee: expect.anything(),
+        })
+      );
+    });
+
+    test('estimate message fee Cairo 1', async () => {
+      const L1_ADDRESS = '0x8359E4B0152ed5A731162D3c7B0D8D56edB165'; // not coded in 20 bytes
+      const estimationCairo1 = await rpcProvider.estimateMessageFee({
+        from_address: L1_ADDRESS,
+        to_address: l1l2ContractCairo1Address,
+        entry_point_selector: 'increase_bal',
+        payload: ['100'],
+      });
+      expect(estimationCairo1).toEqual(
         expect.objectContaining({
           gas_consumed: expect.anything(),
           gas_price: expect.anything(),
diff --git a/__tests__/utils/ethSigner.test.ts b/__tests__/utils/ethSigner.test.ts
index 21b420bcc..a4b39652d 100644
--- a/__tests__/utils/ethSigner.test.ts
+++ b/__tests__/utils/ethSigner.test.ts
@@ -13,6 +13,7 @@ import {
   num,
   stark,
 } from '../../src';
+import { validateAndParseEthAddress } from '../../src/utils/eth';
 import { ETransactionVersion } from '../../src/types/api';
 import {
   compiledDummy1Eth,
@@ -321,4 +322,18 @@ describe('Ethereum signer', () => {
       );
     });
   });
+  describe('Ethereum address', () => {
+    test('Eth address format', async () => {
+      const ethAddr = '0x8359E4B0152ed5A731162D3c7B0D8D56edB165'; // not a valid 20 bytes ETh address
+      expect(validateAndParseEthAddress(ethAddr)).toBe(
+        '0x008359e4b0152ed5a731162d3c7b0d8d56edb165'
+      );
+      expect(validateAndParseEthAddress(BigInt(ethAddr))).toBe(
+        '0x008359e4b0152ed5a731162d3c7b0d8d56edb165'
+      );
+      expect(validateAndParseEthAddress(BigInt(ethAddr).toString(10))).toBe(
+        '0x008359e4b0152ed5a731162d3c7b0d8d56edb165'
+      );
+    });
+  });
 });
diff --git a/src/channel/rpc_0_6.ts b/src/channel/rpc_0_6.ts
index c7754fbb2..f89ce7eff 100644
--- a/src/channel/rpc_0_6.ts
+++ b/src/channel/rpc_0_6.ts
@@ -20,6 +20,7 @@ import {
 import { JRPC, RPCSPEC06 as RPC } from '../types/api';
 import { CallData } from '../utils/calldata';
 import { isSierra } from '../utils/contract';
+import { validateAndParseEthAddress } from '../utils/eth';
 import fetch from '../utils/fetchPonyfill';
 import { getSelector, getSelectorFromName } from '../utils/hash';
 import { stringify } from '../utils/json';
@@ -565,7 +566,7 @@ export class RpcChannel {
   ) {
     const { from_address, to_address, entry_point_selector, payload } = message;
     const formattedMessage = {
-      from_address: toHex(from_address),
+      from_address: validateAndParseEthAddress(from_address),
       to_address: toHex(to_address),
       entry_point_selector: getSelector(entry_point_selector),
       payload: getHexStringArray(payload),
diff --git a/src/channel/rpc_0_7.ts b/src/channel/rpc_0_7.ts
index 7e74e0fa5..3d1f40eca 100644
--- a/src/channel/rpc_0_7.ts
+++ b/src/channel/rpc_0_7.ts
@@ -20,6 +20,7 @@ import {
 import { JRPC, RPCSPEC07 as RPC } from '../types/api';
 import { CallData } from '../utils/calldata';
 import { isSierra } from '../utils/contract';
+import { validateAndParseEthAddress } from '../utils/eth';
 import fetch from '../utils/fetchPonyfill';
 import { getSelector, getSelectorFromName } from '../utils/hash';
 import { stringify } from '../utils/json';
@@ -569,7 +570,7 @@ export class RpcChannel {
   ) {
     const { from_address, to_address, entry_point_selector, payload } = message;
     const formattedMessage = {
-      from_address: toHex(from_address),
+      from_address: validateAndParseEthAddress(from_address),
       to_address: toHex(to_address),
       entry_point_selector: getSelector(entry_point_selector),
       payload: getHexStringArray(payload),
diff --git a/src/utils/eth.ts b/src/utils/eth.ts
index f32431556..d8c2a7536 100644
--- a/src/utils/eth.ts
+++ b/src/utils/eth.ts
@@ -1,14 +1,37 @@
 import { secp256k1 } from '@noble/curves/secp256k1';
 
-import { buf2hex, sanitizeHex } from './encode';
+import { addHexPrefix, buf2hex, removeHexPrefix, sanitizeHex } from './encode';
+import type { BigNumberish } from '../types';
+import { assertInRange, toHex } from './num';
+import { ZERO } from '../constants';
+import assert from './assert';
 
 /**
  * Get random Ethereum private Key.
  * @returns an Hex string
  * @example
+ * ```typescript
  * const myPK: string = randomAddress()
  * // result = "0xf04e69ac152fba37c02929c2ae78c9a481461dda42dbc6c6e286be6eb2a8ab83"
+ * ```
  */
 export function ethRandomPrivateKey(): string {
   return sanitizeHex(buf2hex(secp256k1.utils.randomPrivateKey()));
 }
+
+/**
+ * Get a string formatted for an Ethereum address, without uppercase characters.
+ * @param {BigNumberish} address Address of an Ethereum account.
+ * @returns an Hex string coded on 20 bytes
+ * @example
+ * ```typescript
+ * const myEthAddress: string = validateAndParseEthAddress("0x8359E4B0152ed5A731162D3c7B0D8D56edB165")
+ * // result = "0x008359e4b0152ed5a731162d3c7b0d8d56edb165"
+ * ```
+ */
+export function validateAndParseEthAddress(address: BigNumberish): string {
+  assertInRange(address, ZERO, 2n ** 160n - 1n, 'Ethereum Address ');
+  const result = addHexPrefix(removeHexPrefix(toHex(address)).padStart(40, '0'));
+  assert(result.match(/^(0x)?[0-9a-f]{40}$/), 'Invalid Ethereum Address Format');
+  return result;
+}
diff --git a/www/docs/guides/L1message.md b/www/docs/guides/L1message.md
index eec10460c..8e154b8c8 100644
--- a/www/docs/guides/L1message.md
+++ b/www/docs/guides/L1message.md
@@ -42,11 +42,11 @@ const responseEstimateMessageFee = await provider.estimateMessageFee({
   from_address: L1address,
   to_address: L2address,
   entry_point_selector: 'handle_l1_mess',
-  payload: ['1234567890123456789', '200'],
+  payload: ['1234567890123456789', '200'], // without from_address
 });
 ```
 
-If the fee is paid in L1, the Cairo contract at `to_Address` is automatically executed, function `entry_point_selector` (the function shall have a decorator `@l1_handler` in the Cairo code), with parameters `payload`.
+If the fee is paid in L1, the Cairo contract at `to_Address` is automatically executed, function `entry_point_selector` (the function shall have a decorator `#[l1_handler]` in the Cairo code, with a first parameter called `from_address: felt252`). The payload shall not include the `from_address` parameter.
 
 ## L2 ➡️ L1 messages